Electric toothbrush - how often to change? Not the head - the whole thing!

[Jungfraujoch]

Curious - my dentist suggested getting a new one - tbh can’t remember how old mine is - maybe 3/4 years. Obviously I change the actual brush head regularly!

When it stops working? Mine is twelve years old - it doesn't hold it's charge quite as long as when new but it still does a good job cleaning my teeth.

Why would you need to change it if it's working? I've had mine for years and it's the same as when I first got it

When it breaks? Why would it be anything else?

I change mine every few years. Currently using the io8 for the past year

When it breaks/can’t hold a charge.