Sterilising

Some people say six months because by that stage they are putting everything in their mouths but the NHS recommends doing it until they are 12 months https://www.nhs.uk/baby/breastfeeding-and-bottle-feeding/bottle-feeding/sterilising-baby-bottles/

If you are using formula you have to sterilise as long as you are using formula, as there's a specific bacteria that's really bad for babies that grows from the formula 😊 so usually just after 1 year when you transition to cows milk, but if you choose to use stage two formula then you need to keep sterilising- dummies etc are fine to stop sterilising at 6 months I think? 😊

It's when you stop using formula that you stop sterilising bottles . So there is no specific age

It's typically 12 months.
Dummies are also 12 months

At 6 months you don't need to sterilise cups and bowls, spoons etc