Hi, our baby is 5 weeks and colief has been a life saver for us! So i really dont mind the 30 mins wait before each feed, just means ive to be a bit more organised which is no bad thing.. I would premake my formula for night feeds, i make them up as normal but with only 2 drops of colief then pop in fridge for a minimum of 4 hour but no longer than 12 hours as per instructions provided...