quarantine duration

[Paleosuchus]

Hey, i am alittle confused on the time period of which to quarantine a new reptile. I have heard many different periods, one month, two months, and recently was told after the second defication. Just wandering how long you all quarantine your new animals? Aswell as when you know it is safe to add them to the rest of the collection and not to got further with the quarantine? Thanks for any help, jason