Product Lifespan & Replacement Planner
Typical lifespans for 35 home systems, appliances and pieces of gear — enter the install year and get a realistic remaining estimate.
Typical lifespans from home-inspection and manufacturer guidance. Climate, usage and maintenance move every number — a serviced furnace outlives a neglected one by years. Budgeting rule of thumb: save 1–2% of your home's value per year for replacements.
Something breaks every three and a half months, forever
Each item in the table above lasts some number of years, so each contributes one-over-that replacements a year. Add them up across all 35 items — lifespans from 4 to 100 years — and the household rate falls out:
3.38 replacements a year, or one every 3.5 months
Nobody budgets like that, because nobody adds the list up. Each item gets considered on its own, where a fifteen-year appliance feels like a problem for later. The rate does not depend on how old anything currently is — it is what the list settles to once the ages have spread out, which for a house you have lived in a while is roughly where you are.
But they do not arrive on schedule
An average of 3.38 a year does not mean three or four a year. Simulating 2,000 households over 40 years, each item starting at a random age and then renewing on its own clock:
| In a given year | Replacements |
|---|---|
| mean | 3.38 |
| median | 3 |
| 90th percentile | 6 |
| 99th percentile | 8 |
| worst seen | 13 |
Only 2.7% of years have nothing to replace at all, while 24.3% have five or more. A quarter of all years are noticeably worse than the average, and one in a hundred is roughly double it. Planning against the mean is planning for a year that happens less than half the time.
The simulated mean agrees with the arithmetic above, which is the check that the spread is real rather than a modelling artefact. This is simply what a renewal process does: independent clocks running at different speeds do not politely take turns, they bunch. Nothing has gone wrong in the bad years and nothing was saved in the quiet ones.
And the count is dominated by the cheap things
Sorting by lifespan, the 10 shortest-lived items — of 35 — account for half of all replacements:
| Shortest-lived | Years |
|---|---|
| Car battery | 4 |
| Smartphone | 4 |
| Laptop | 5 |
| Wi-Fi router | 5 |
| Car tires | 6 |
Everything lasting twenty-five years or more accounts for just 3% of the events between them.
That changes how the headline reads. "One replacement every 3.5 months" sounds alarming and mostly is not, because half of those events are a router or a set of tyres rather than a roof. The roof is in the other half — and it is the half that decides the budget, while the first half decides the rhythm.
How to use
- Find the item you are asking about.
- Enter the year it was installed or bought.
- Read the typical lifespan and remaining estimate.
- Treat maintenance history as more important than age alone.
Frequently asked questions
How reliable are typical lifespans?
As averages, reasonably; for any individual item, loosely. Usage, maintenance, water hardness, climate and installation quality all shift the figure substantially. A well-maintained item routinely outlasts a neglected one by years, so age alone is a weak predictor.
When should I replace rather than repair?
A common rule of thumb is to replace if the repair costs more than about half the price of a new one, or if the item is near the end of its expected life. Efficiency matters too — an old appliance can cost enough in running costs to justify replacing before it fails.
Why do things seem to last less than they used to?
Partly genuine — cost pressure has reduced material thickness and made repair harder, and electronic controls add failure points that mechanical ones did not have. Partly not: survivor bias means the old appliances still running are the good ones, and we do not see the ones that failed decades ago.
Does maintenance really extend life?
Considerably, for anything with a filter, a moving part or a water connection. Filters, descaling, cleaning coils and clearing drains address the failure modes that account for most premature deaths of appliances, and they cost very little.
Is an extended warranty worth it?
Usually not, on the arithmetic. They are priced to be profitable, most failures happen either very early — within the standard warranty — or well after the extension expires. The exception is where a single repair would be genuinely unaffordable rather than merely annoying.
Should I replace something before it fails?
For anything whose failure causes damage rather than inconvenience, yes. A water heater or a washing machine hose that fails can flood a house, and replacing them near the end of their expected life is far cheaper than the water damage. For a toaster, wait for it to break.
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