My 2001 Prius lasted 10 years
My 2001 Prius lasted 10 years and 330,000 miles before it quit keeping up with traffic at highway speeds going uphill because, presumably, too much energy was going into trying to continuously charge the failing batteries (gas mileage was down to around 36-38 MPG from a high of around 50 MPG). I probably would have replaced the battery (the outstanding individual cell troubleshooting and replacement information wasn't available at that time), but the dealer said "their computer" wouldn't connect with the car and they wanted me to pay $900 to replace a box just so they could troubleshoot the vehicle. Fat chance. I traded it in on a Rav4 -- the worst vehicle I have ever driven, which was traded in a few months later for a Subaru Outback, the best vehicle I have ever owned.