Natasha
This is a debated topic and I can only tell you what I personally do or have been told.
How long can bottles still be ok to give babies while out of the fridge?
My HV and maternity hospital said 1hr, I personally leave then out longer if I have made then, left them to cool and forgotton to refridgerate them.
Also if you don't heat up a bottle and baby is happy to take a bottle at room temperture and they have drank some how long after that can you no longer give them anymore?
Bacteria from your LO mouth transfers back into the bottle and speads very fast, so I don't reuse after Calum has had enough. Others have posted different, so you will get difference of opinopn here.
HTH's