Every home inspection report contains a version of the sentence “at or near the end of its serviceable life”, and almost nobody knows what to do with it. It is not a repair order. It is a hint that you should start saving.
The useful thing about lifespans is not the numbers themselves. It is knowing, at any given moment, which two or three things in your house are in their final third — because those are the ones that should be in a budget rather than a surprise.
The table
Typical service life under average use, with routine maintenance.
| System | Typical life | Notes |
|---|---|---|
| Asphalt shingle roof | 20–25 years | Architectural shingles reach the top of the range, three-tab the bottom |
| Metal roof | 40–70 years | Coating may need renewal sooner |
| Tank water heater | 8–12 years | Hard water shortens this materially |
| Tankless water heater | 15–20 years | Only with periodic descaling |
| Furnace | 15–20 years | Annual service moves this several years |
| Central air conditioner | 12–17 years | Outdoor coil cleanliness matters more than people think |
| Heat pump | 12–15 years | Runs year-round, so it wears faster than an AC-only unit |
| Ductwork | 20–30 years | Usually fails at joints and seals rather than wholesale |
| Water softener | 10–15 years | |
| Garbage disposal | 8–12 years | |
| Dishwasher | 9–12 years | |
| Clothes washer | 10–13 years | |
| Clothes dryer | 10–13 years | Vent condition affects this and fire risk together |
| Refrigerator | 12–15 years | Condenser coil cleaning helps |
| Range / oven | 13–15 years | Gas typically outlasts electric |
| Sump pump | 7–10 years | Failure is usually discovered during a storm |
| Garage door opener | 10–15 years | Springs wear faster, 7–12 years |
| Exterior paint | 7–10 years | Highly dependent on exposure |
| Interior paint | 5–10 years | |
| Carpet | 8–10 years | |
| Smoke and CO detectors | 7–10 years | Replace the unit, not just the battery |
Treat every number as a range with a wide error bar. A well-maintained furnace in a mild climate and a neglected one in a hard-water, high-dust house are not the same appliance.
What actually moves these numbers
Three things account for most of the variation.
Whether it has a filter, and whether you change it. Anything moving air or water through a filter degrades quickly when that filter is clogged. A furnace working against a blocked filter runs hotter and cycles more, and both shorten its life. This is the cheapest lever available and the most commonly ignored.
Water hardness. Scale is the quiet killer of water heaters, dishwashers, kettles and tankless units. In hard-water areas the low end of every water-related range is the realistic figure unless you soften or descale.
Run time, not age. A heat pump in a climate that uses it year-round wears faster than the same unit used four months a year. Age is a proxy for hours, and it is a bad proxy in unusual climates.
Two things that matter less than people assume: brand, beyond the broad budget-versus-premium split, and initial cost. Installation quality and maintenance dominate both.
Fail-in-place versus replace-early
The right strategy differs by what happens when the thing dies.
Replace before failure when the failure mode causes collateral damage or leaves you exposed:
- Water heaters, because a tank failure floods whatever it stands on
- Sump pumps, because they fail exactly when needed and usually silently
- Furnaces, if you live somewhere a February failure is genuinely dangerous
- Roofs, because the damage compounds into the structure underneath
- Washing machine hoses, which are not a lifespan question so much as a five-year replacement habit
Run to failure is a perfectly rational choice for most things that simply stop working: dishwashers, ovens, disposals, dryers. The inconvenience is real, the damage is not, and you get the last few years of use you paid for.
How to actually use this
The table only becomes useful once it is attached to your specific house.
Go through and write down the age of the big six: roof, water heater, furnace, air conditioner, sump pump if you have one, and the electrical panel. Most of these are on a data plate, and if you have a home inspection report from your purchase, the inspector already recorded them.
Then note which are past two thirds of their expected range. Those are your next expenses, in rough order.
This is exactly the record we built Roots to hold, with recurring reminders attached to each system so the maintenance that extends those lifespans actually happens. Reminders are free and uncapped, which is more than enough for a whole house.
The takeaway
Spend twenty minutes today writing down the age of your roof, water heater and furnace. Those three account for most of the large, unavoidable spending in a house, and knowing where each one sits in its range turns the next decade from a series of emergencies into a schedule.