We calculated the typical price for both an expensive premium version of a given appliance, as well as a cheap and cheery budget one by taking the first and third quartiles of the prices of currently available models. This gives us a statistically robust estimate, but please remember that's what it is – an estimate.

Next, assuming linear depreciation, we calculated the value per year of life by taking the purchase price and dividing it by our estimated life expectancy for that appliance. If the estimated life expectancy is 10 years, the annual depreciation for a premium appliance purchased for $1500 is $1500 / 10, or $150 a year. For a budget model purchased for $500, it's $500 / 10, or $50 a year.

We then looked at the typical repair cost for that type of appliance. This cost will vary wildly depending on the nature of the repair and the cost of parts required, but again this is just a starting point – a minor repair will be cheaper and tip the scales in favour of repair, and a major one will be more expensive and tip the scales towards replacement.

If the typical repair cost is $300, we subtract $300 from the initial purchase price, then divide the remainder by the annual depreciation amount – that tells us how many years until the residual value of the appliance is less than the cost of repairing it, at which point it makes better financial sense to replace the appliance.

In our premium appliance example: $1500 – $300 (purchase price minus repair cost) = $1200.

$1200 / $150 (divided by annual depreciation amount) = 8 years.

For the budget appliance example: $500 – $300 = $200. 

$200 / $50 = 4 years.

So while the appliance is estimated to last for 10 years, it's cheaper to replace it between 4 and 8 years depending on how much you paid for it in the first place*.

Assumptions:

• Depreciation is linear.
• Improved efficiency and reduced operating costs of newer appliances can be ignored.
• Life expectancy is the same across all products in a given category, regardless of price.
• Repair costs are the same regardless of the purchase price of the appliance.

*Formula – Divide the average cost of the appliance (budget or premium, calculated as first and third quartile of currently available models in our tests), by the appliance's estimated lifespan to calculate depreciation per year. We consider the appliance is cheaper to replace than to repair when residual value is less than the average service price. Where specific repair costs were unavailable, we took the average service cost from hipages.com.au.

How long should your appliances last?

Knowing roughly how long your household appliances should last can help you plan to keep them running smoothly.

• Air conditioners: 12 years
• Fridges: 10 years
• Washing machines: 10 years
• Clothes dryers: 10 years
• Column heaters: 10 years
• Dishwashers: 9 years
• Barrel vacuums: 8 years
• Televisions: 7 years
• Laptops: 5 years
• Smartphones: 4 years.

• Life expectancy: 10–11 years
• Cheaper to replace: 8–9 years
• Average repair cost: $300

Faulty thermostats and damaged door seals are worth repairing, and the cooling performance of an older fridge can be partially restored by replacing worn seals. If your fridge is more than six years old and suffers a major fault (such as compressor failure), then consider replacement because a new one will be more efficient and have lower running costs.

Read our guide to making your fridge last longer.

• Life expectancy: 9–10 years
• Cheaper to replace: 6.5–8 years
• Average repair cost: $300

It's cheap and easy to replace broken racks, seals, inlet valves and hoses, even on relatively old machines, and most manufacturers keep spare parts for years. Keep in mind that newer models are quieter and more efficient. Definitely get a quote before repairing electronic components – it may not be worth it.

Read our tips for making your dishwasher last longer.

• Life expectancy: 13–15 years
• Cheaper to replace: 10–12 years
• Average repair cost: $350

Good news if you love your oven: if parts are available, then even an old model is well worth repairing. Broken doors, thermostats, simmerstats and elements are easy to fix. Broken fans and electronic panels can be more expensive, but a new oven won't save you much on running costs so it's worth looking into. Expensive freestanding ranges ($5000+) are almost always worth repairing.

Is it time to go shopping? Read 5 signs you need a new oven.

• Life expectancy: 13–15 years
• Cheaper to replace:
• 10–11 years (induction cooktop)
• 7–10 years (ceramic cooktop)
• Average repair cost: $280

Older style resistance elements and element controls are easy to fix, so it's worth getting them repaired. Electronic modules and induction coils can be expensive, so it may be time to upgrade if they fail outside of warranty. Given the health risks and the rising cost of using gas in the home, if you experience a major fault with a gas stove, it could be a good opportunity to upgrade to a cleaner, more efficient induction stove.

• Life expectancy: 8–9 years
• Cheaper to replace: 0–2 years
• Average repair cost: $250

Microwaves are relatively cheap, so if it's out of warranty consider replacing it for all but the simplest repairs (such as replacing glass platters, which are generally fairly cheap). It's worth repairing more expensive models (combination convection microwaves for example) up to about five years old, but magnetron failure or a damaged door or cabinet usually means a trip to the shops. Be sure to check our microwave reviews before you buy.

• Life expectancy: 4 years
• Cheaper to replace: 0–2.5 years
• Average repair cost: $150

Bowls and mixing paddles can be easily replaced, but get a quote and think carefully before repairing anything else. If you find you're ready to buy a new model, see our breadmaker reviews.

• Life expectancy: 4 years
• Cheaper to replace: 1 year (probably won't have spare parts available)
• Average repair cost: $150

It's unlikely you'll be repairing small appliances such as these – they're just not worth the trouble. But you should be able to get a faulty one replaced for up to a couple of years after purchase, either under warranty or through your rights under Australian Consumer Law.

Do you like your appliances to match? Check out our pick of the best toaster and kettle sets.

• Life expectancy: 4–7 years
• Cheaper to replace: 0–4.5 years
• Average repair cost: $170

There's huge variation in food processor price and quality, so whether you should repair or replace yours depends on its value.

It's usually worth replacing broken bowls, blades and accessories, but unless you've got a really expensive mixer, major failures like motors generally mean replacement.

Wondering which appliance would be best for you? We explain the difference between food processors, mixers and blenders.

• Life expectancy: 10–11 years
• Cheaper to replace:
  • 7–8.5 years (front loading washing machines)
  • 7–7.5 years (top loading washing machines)
• Average repair cost: $300

From our 2023 product lifespan survey, based on 687 responses from owners having experienced a major issue with their current or a previously owned washing machine. Numbers in brackets are the number of respondents for each brand.

Note: This is the average time before a major fault occurred in washing machines from each brand. This is different to the total life expectancy of the appliance, as many of these faults were repairable, not terminal.

Repairing should be your first option because washing machines are expensive to buy and repairs may be simpler than you think – for instance, clearing a blocked pump in a front loader is usually a DIY job that doesn't require tools. Broken door seals are also easy to fix, as are switches and mechanical timers. Even seemingly terminal failures may be a relatively simple repair – a drum that no longer spins could be remedied by replacing a drive belt.

However, once your washer is more than six years old, a major failure usually means getting a new one. You're generally looking at replacement if the electronics, motor or gearbox fail, or for faults costing over $300 to fix.

Read our other tips for making your washing machine last longer.

• Life expectancy: 10–11 years
• Cheaper to replace:
  • 8.5–9 years (heat pump dryer)
  • 6–7 years (vented dryer)
• Average repair cost: $250

Vented dryers are simple and can be easy to repair so it's usually worth it – drive belts, thermal fuses and even the motor can be replaced relatively easily, and door catches, controls and lint filters should be readily available. You also won't realise any running cost savings from a newer model because it won't be any more efficient than your old one. On the other hand, vented dryers are relatively cheap to replace.

At the other end of the dryer spectrum, a heat pump dryer is a complicated beast – this complexity means repairs may get expensive, but their high price tag means you should think twice before ditching your old one. Just make sure you get a quote for any repairs.

Is your clothes dryer past its prime? Check our clothes dryer reviews to find best model for you.

• Life expectancy:
  • 5 years (cordless stick vacuum)
  • 8 years (barrel or upright vacuum)
• Cheaper to replace:
  • 1–4 years (cordless stick vacuum)
  • 0–6 (barrel or upright vacuum)
• Average repair cost: $225

Jammed brush rolls and blocked filters can be unclogged or replaced quite cheaply, as can frayed or broken hoses and accessories. Vacuums vary wildly in price and quality, so major faults like broken switches or burned out motors can cost as much as a replacement, especially for cheaper models. Advances in technology mean vacuums are moving towards cordless hand-held models, so if your older barrel vac stops working, it could be a good excuse to switch.

The most common problems with cordless vacuums are battery or charger faults – parts that are usually easy to replace.

Here are the signs you need a new vacuum cleaner.

• Life expectancy: 7–8 years
• Cheaper to replace: 4–6 years
• Average repair cost: $400

From our 2023 product lifespan survey, based on 457 responses from owners having experienced a major issue with their current or a previously owned television.

Note: This is the average time before a major fault occurred in TVs from each brand. This is different to the total life expectancy of the appliance, as many of these faults were repairable, not terminal. Numbers in brackets are the number of respondents for each brand.

If you've got an old telly, you're usually better off replacing it. TV technology advances rapidly and major manufacturers are releasing new models each year, so buying a replacement gives you better picture quality and a raft of new features, like media streaming.

For newer TVs, though, it's worth getting a quote – seemingly terminal faults may be as simple to fix as replacing a cheap capacitor, or may require an entire circuit board costing as much as the entire TV. The panel itself should last for 10 years or so but usually can't be repaired, so dead pixels, cracks or other damage, unless you learn to live with them, are usually terminal.

Here's our expert advice on how to buy a great smart TV.

• Life expectancy: 5 years
• Cheaper to replace: 4.5 years
• Average repair cost: $150

While we expect computers to last five years, according to US organisation Consumer Reports, around one in three fail by the fourth year.

Power supplies and batteries for laptops are an easy replacement at any age, but consider an upgrade if your motherboard or screen fails. A failed hard drive on a two-year-old computer could be used either as a chance to give it a new lease of life with more storage or a faster solid-state drive, or as an excuse for an upgrade.

With computers it's not just the hardware you've got to consider. Older computers may struggle to run modern resource-intensive operating systems. If yours is straining under the weight of a new operating system, it's time to say goodbye.

Likewise, if your OS is no longer supported with security updates, then ditch it because your digital security could be at risk. Speaking of security, depending on the sophistication of a ransomware or other malware attack, it may necessitate replacement.

If you're ready to upgrade your laptop, do the planet a favour and recycle your old computer.

• Life expectancy: 4.5 years
• Cheaper to replace:
  • Often determined by battery failure. Batteries can cost 60% of the price of the phone.
  • For non-battery-related faults: 3–4 years
• Average repair cost: $300

Although manufacturers may try to convince you to replace your $1000 flagship phone each year, you should expect it to last for three years at a minimum, and much longer if you opted for a top-of-the-line handset.

A common problem (usually not covered by warranty) is a damaged screen. If you've cracked the screen on an expensive phone, it's usually worth getting it repaired – especially for newish phones. There are many third-party businesses that can do this for you, but get a quote first as it can be expensive.

Regardless of age, if your phone's working well but the battery fails, then picking up a new battery online can bring your old phone back to life (provided it's easy to change).

Consider a replacement phone after the two-year mark for major faults, if your phone's becoming slow and laggy, if you're paying extra for a plan that includes a new handset every couple of years, or you can no longer push back against the fickle winds of fashion.

Here are four tips to extend the life of your phone battery.

• Life expectancy: 10 years
• Cheaper to replace: 3–7.5 years
• Average repair cost: $285

Most problems with expensive high-end components should be fixed, but make sure you get quotes first. For cheaper systems and soundbars you're probably looking at a replacement for all but the most minor issues, and even if the fault's covered under warranty, it's unlikely manufacturers will maintain an inventory of spare parts.

If yours has given up the ghost, read our guide to buying the best soundbar.

• Life expectancy: 8 years
• Cheaper to replace: 5–7 years
• Average repair cost: $450

Only newer, high-value cameras are worth repairing. Replaceable lenses for a DSLR can often be replaced for less than the cost of repairs – particularly the lower-end 'kit' lenses supplied with the camera body. If it's not covered by warranty, then view it as an opportunity to get a better one.

While you might opt to repair a five-year-old DSLR camera body, a failed five-year-old compact should be treated as an excuse to upgrade because new models will offer better technology and take better photos. See our DSLR camera reviews for the best of the latest models.

• Life expectancy: 3 years
• Cheaper to replace: 0–2 years
• Average repair cost: $150

Only get your printer repaired if it was expensive. Printer manufacturers make their profit from the ink, so a new printer can be had without paying a small fortune (not to mention it'll probably give you better features than your old one). If you do a lot of printing, it may be worth spending a little more on a tank printer, which can bring down the cost of replacement ink.

If your printer is playing up, our guide to cleaning your printer may help you eliminate certain issues.

• Life expectancy: 9–10 years
• Cheaper to replace: 2–4.5 years
• Average repair cost: $300

Repair or replace? Dehumidifiers are usually fairly reliable, but it's not worth repairing a cheaper model if it develops a major fault out of warranty, such as compressor failure.

• Life expectancy: 10–15 years
• Cheaper to replace:
  • Small model: 7–8 years
  • Medium model: 8–9 years
  • Large model: 8.5–9 years
• Average repair cost: $300

An air conditioner is an expensive appliance to replace and doing so may require a bit of structural work on your house if you need to run new ducting or wiring. Parts may be hard to get for older models though, and after five to 10 years, they just might not perform as well as they did when new.

Air conditioners are also energy-intensive appliances, and upgrading an older R410a model to one using the more efficient R32 refrigerant will lead to a significant reduction in running costs, may be quieter both inside the house and for your neighbours (a particular pain point with air conditioners), and offer new features such as Wi-Fi controls. Minimum energy performance standards (MEPS) were also tightened up in 2013, so if your air conditioner IS more than 10 years old, a new one is required to be more efficient by law.

A broken air conditioner is likely to get expensive no matter whether you opt for repair or replacement, so it's a good idea to get quotes for both options before deciding.

• Life expectancy:
  • 5 years (fan heater)
  • 10 years (oil column, radiant or convection heater)
• Cheaper to replace:
  • 0–3 years (fan heater)
  • 0–2 years (oil column, radiant or convection heater)
• Average repair cost: $300

Many heaters are so cheap that repairs aren't worth considering (or the manufacturer will just replace it under warranty rather than keep a supply of parts), while the more expensive oil column heaters might not be repairable at all. Remember your rights under Australian Consumer Law if your heater doesn't last into its second winter, even if the warranty's a little shorter than that.

Older heaters without safety features like safety tip-over switches and cool-touch housings should be replaced as a matter of course.

Check out our electric heater reviews to find out which of the latest models perform best.