Dad’s short answer: Eight to ten years or more on a maintained machine — these are simpler than most appliances. What fails is almost always a consequence of skipped maintenance: clogged lines, perished seals, or a worn brush, rather than the motor giving out.

What actually fails

Pump and spray lines clog, usually from detergent residue or hard water scale that built up because the machine was never flushed with clean water. That shows up as weak or uneven spray.

Seals and gaskets perish, and a bad tank gasket means the machine can't hold suction. People often mistake this for a dying motor when it's a cheap part.

Brushes wear out, which degrades cleaning long before anything looks broken.

Hoses crack at stress points, particularly where they flex near the handle.

The motor is usually the last thing standing, which is why a machine that's rinsed out after every job can genuinely go a decade.

The parts check before you buy

Search for replacement brushes, tanks, gaskets and hoses for the specific model and confirm you can get them today. Same two-minute check I recommend on robot vacuums, floor washers and vacuums, and it matters here too.

Also check formula availability, which is its own issue on machines tied to a proprietary solution. A machine you can't feed is as dead as one you can't repair.

And weigh this: these machines sit unused for months at a time, which is exactly when residue hardens in a line. If you're storing one for a season, flush it thoroughly first and store it dry with the tanks open. That's the single best thing you can do for its lifespan.

Dad’s Take: Flush it before you store it for the season. Residue hardening in the lines over a winter is what kills these machines.