Bottles sterilize or nay

After 8 months because we finally got a dishwasher. I'll still use it occasionally at 2 for his bath toys

At 6 months

12 months

When he turned 1 and started using proper cups instead

Depends where you live as guidance will differ. In the UK you should sterilise until you stop using formula.

I never did

12 months. There no need to sterilize bottles after that. What i do now is i wash and boil them from time to time