once you see the sacks its normally 1-2 days but not good to gamble because they can pop in couple of hours on you and you may also be not seeing them all. You should take a spray bottle and wet the shit out of the hermie then get it out of the room. The spraying will kill any pollen that gets stirred up while moving. Why would you want to wait until the last minute, get the hermie out now and make some hash out of it. Dunno why you would wait its not going to grow much, how far along are you?