My ifc asked me to bring 2 bottles daily, they will wash and sterilise. I guess every ifc is different, you better check with them.
As for no of servings, it depends on how frequent your baby normally feeds, then maybe add 1 serving in case baby gets hungry faster than usual. Like for example my baby feeds every 4 hourly, and she spends about 10 hrs in ifc, so I normally pack 3 servings using those stacked milk container.
Tan Zhi Yi