I traded in my Camry Hybrid with 88,000 miles on it, and the gas mileage had taken a hard tumble (from 39mpg to 34 mpg) in a fairly short period of time. I suspect the battery was on its way out. My "new" Prius C (2016) had 22,800 when purchased and I have a feeling the battery in it will last a lot longer. My daughter has a 2012 Prius C with 150,000+ miles and she replaced the 12-volt battery and the actuator on the driver's side door, and that's it. I'm hoping for similar results.
From what I've read so far, the way to win at Prius is to get the car young, put your miles on fast and get out before the calendar catches up to the odometer.
