It's interesting that different hospitals have different storage guidelines, so it is important to check with the hospital on that. It's personal preference. If space is a concern, milk storage bags don't take up as much space in a freezer. If you use plastic bottle liner bags, then you need to put those bags into a large freezer bag or some other container. Odors can penetrate the thickness of those bags, so you need some form of double-bagging.
Some babies have very strong preferences for one nipple over another.
If one doesn't work well, try another. Don't buy more than one of any kind until you know. Real world questions answered by our volunteer LCs, tips, techniques, and more. Important Disclaimer . Consult with your lactation consultant or health care provider regarding the advisability of any opinions or recommendations with respect to your individual situation.