we went when belle was 5.5 months and took 2 boxes, she only used one but i wanted to make sure we didnt run out. She was on 4 bottles a day as we hadn't started weaning properly and we went for 12 nights.
i tookm a mix of tins and cartons, i was also still breastdeeding but she was being topped up by bottle too.
The cartons make it easy for an emergency or back up being out all day x