According to Wrightgrid, you can expect your Toyota Prius battery to last between 10 and 15 years, especially if you take good care of it. However, there are a handful of factors that go into what makes a “healthy” battery. Wrightgrid noted that you can determine how quickly your Prius’ battery is deteriorating by the frequency of voltage spikes, but you should get about 150,000 miles at the bare minimum before seeing any sort of problems in your car’s handling.
You can keep your battery charged by driving your vehicle regularly, and by keeping is gassed up so that you aren’t relying so heavily on your hybrid EV system. It’s not unlike charging a very large phone; the healthiest charge level is somewhere between 30-80% at all times. You may also want to limit the number of “short” trips, or tours through populated urban spaces with many stop lights — or spaces with heavy traffic. Trips like these can put stress on your car’s battery that lowers its lifespan. You may as well balance these trips out with a few longer trips to lower-density spaces such as freeways and rural roads, where you can give both your gas engine and electric motor some regular exercise.