Personally I'm going to reuse the bottles and any nipples that weren't used too much. I know that sounds vague, but when I stored them, I wrote on the bag if they weren't used very long, such as the newborn ones cause she moved up in sizes pretty quickly. However, the 3s or 4s I know she used for quite awhile so I'll probably replace those. I just put ours in the dishwasher for cleaning them, no boiling, but a good clean with hot water. Bottles thesedays are made with hard plastic so they should be okay I would think even if you replace the nipples. HTH