N.
I used Avent and other brands of bottles for my first and saved all of them for my second (4 years later). Because my first had reflux, we went thru a lot of different bottle brands to find the ones that gave her the least problem, but my second didn't have those issues so we ended up only using the Avent bottles for him. We used what I had saved from my daughter, bought I think 1 package of new and also picked up several real cheap (like 5 big and 3 small) from a garage sale for a dollar. I replaced all the nipples with new ones of course, and thoroughly sterilized all the bottles, rings and lids. They worked as great with my second as they did my first. And it was great having a plethora of Avent bottles for my second. I didn't have to wash/sanitize so often. :-)