How long does a treadmill last?

Normally a treadmill lasts for 7-10 years and with instructed care and maintenance, it can achieve a longer lifespan. Again, if you buy a treadmill from a bad brand and its build quality is poor then it can become useless in a year or so. It's hard to say for sure given the fact that so many factors go into determining the longevity of a treadmill.