Hi, if you're changing from breast to bottle, you definitely want to make sure that bottles and nipples are sanitized. You'd want to have a good amount of bottles and such supplies so that you're not constantly cleaning and have fresh ones to go to in the middle of the night or early morning feedings. Some people prefer a particular brand. I looked for ones that tried to reduce the amount of air. My boys were preemies, so it felt like I was always buying a new batch of bottles and nipples per his growth (more holes to allow flow).
Hope this helps,