Not sure whether we need to move up from MAM size 2 teat to size 3. Baby is five months old and a hungry, healthy chunk. He’s taking between 6 and 7 ounce bottles every 3 to 4 hours and only once just before dawn in terms of night feed. Each feed is taking about 10 to 15 minutes. In the last week he started to get occasionally frustrated or upset at the bottle. There is also a lot of bubbling in the teat cavity. I can’t remember if my eldest ever even went onto size 3 and I know some posts here suggested it was too fast for them. The MAM website suggests that size 3 teats can be used from four months. Interested in the range of opinions.