We get this question weekly, usually from someone comparing quotes. The honest answer: a correctly applied pump in clean water should give you 10 to 20 years. A badly applied one can fail in eighteen months, and we have seen both from the same model.
Three decisions decide most of the lifespan before the pump ever runs:
1. Sizing
A pump running at the extreme ends of its curve works hard, vibrates more and wears faster. The middle of the curve is where bearings and seals are designed to live. Buy the pump that cruises, not the one that sprints.
2. Duty cycle
A motor rated for intermittent duty will cook in continuous service. Match the nameplate duty to the job, not to the invoice total.
3. The water itself
Sand, grit and aggressive chemistry are pump killers. If the well carries sediment, the fix is filtration or a design rated for it, not hope.
After those three, the variables are smaller: seal quality, motor insulation class, stainless versus cast construction. They matter, but they cannot rescue a pump that was wrong for the job on day one. Get the first three right and the rest is detail.