After how long should I replace the bottle and pacifier?

I did when I had my son, with boiling them to make extra sure they were sterile I change the nipples every 1 1/2 to 2 months, I had the disposable bottles with the bags. I used that until the formula stage was over.Then went to normal bottles, I kept the bottle a little longer than the nipples. What i always did/ still do, is think if I would use it if it were me. That really does work, you look at everything for your child as well or better than ourselves. That pacifier, was long gone before he crawled, I didn't want my son clinging to that thing and take a chance in shifting his teeth.
I know we all want to do right no matter what, if your ok with the bottle keep it. I don't know your income, I would change the nipples though, they really hold germs longer. (like the medical say about our hands). Hope this helped some if any. Take care

Mine work perfectly fine, well the binkis at least (she's been off bottles for like 6 months). My bottles were still good at a year though and I probably could've used them longer.

I think the "buy new ones @ 6 months" think is just like buying a new toothbrush every 6 months. Its not completely necessary, but probably more sanitary.

The rubber ones will dry rot that's why you need to replace them, if you're using the silicone ones just check for tearing and make sure you keep them well sterilized.

My son used the same bottles from birth to 12 months. I never replaced them. I say as long as they are functioning well, not icky, and the nipples arent all cracked an nasty, they are fine :)