Bottle fed babies

My little boy is taking 3oz each feed, he is 9 days old. It's advised to use a new bottle for each feed and to also give baby the milk within an hour of making it up. We have about 8 bottles, sterilise them in the daytime for the day feeds and then sterilise again at night time for night feeds. This works well for us.

My 2 and half week old takes 3-4oz and we use a sterilise bottle every feed.
Health visitor said bottle can stay for 2 hours when made however little one tends to take it within the hour x

Once baby has started drinking the bottle it needs used within 1 hour. If they haven’t it can be kept at room temperature for 2 hours before it needs to be discarded x

3oz had to change bottle and teats slow flow because he was gulping too much air and not gaining weight back since changing he’s gone from 8lb 3 to 8lb 8! X