I ordered these nipples because they are the next step up from the one hole newborn nipples. I waited until my baby was 5 weeks old to use these because I thought the flow might be too much for her. She didn't have any problem with them as they are still slow. They probably speed up feeding time by 5 or 10 minutes. The baby has had no problem with Avent bottles and nipples. Sometimes they leak so you have to check them before you give them to baby. The remedy is simple...just unscrew the nipple holder and screw it back in and make sure it is tight. I would definitely recommend avent nipples and bottles. These nipples probably aren't a necessity, but they do get the baby used to a quicker flow.