Baby bottles question?

hi i used avent and my son was sucking in 2 much air so i had to change to dr.brown and i would definitely recommend dr brown they are a brill bottle i had 3 of them for my son and was grand but if you dont wanna sterilise all bottles till the evening time youd be better getting 12-15 but if u plan on doing them as soon as there finished 6 or that be grand