How long are the batteries in my 2006 Toyota Prius likely to last?

I have a 2006 Toyota Prius with which I have been very pleased. It is approaching four years old, half the guaranteed battery life, and I wondered if you have any evidence of when Prius batteries tend to fail. Should I be considering replacing the car now, or should I wait until just before the price begins to plummet as the 8-year point approaches? When do you think that might be?

Asked on 10 October 2010 by DH, Galashiels

Answered by Honest John
I can’t tell you. There are still plenty of Mk 1 Prius driving about. The extremely good news is that Toyota is seeing Prius IIs used as taxis with over 400,000 miles on them. They are exceptionally reliable, have a very gentle powertrain, and less to go wrong than a conventional car. They actually make a very good secondhand buy.
Similar questions
I own two Honda cars which, at 18 years old, are now coming to the end of their economic lives. So I now need a new or secondhand car to replace one of them - probably the Legend. The other is a 1.6i Civic....
I have owned from new a 2006/56 Toyota Prius for five years. At 15,000 miles per year, the current mileage stands at 75,000. It has been maintained by Toyota throughout, and apart from the failure of the...
Does this win the prize for the most optimistic claim for product failure? Last week my dealer-maintained Rover 75's original manufacturer-fitted battery failed after barely nine and a half years. Is Rover...
Related models
Much better than the original. An enjoyable, practical, safe, economical hybrid. Looks good, too. Prius Taxis have run to 400,000 miles plus with very little trouble.
 

Value my car