Leave it in for as long as you feel comfortable with. I regularly leave a roll of Velvia 50 in my camera for anything from 3 to 4 months. Neither myself nor a medley of printers have ever brought up anything relating to spoilage of any film I have used.

A roll of Provia 100F has been in my Zero Image Pinhole since late June. B&W films IIRC degrade very, very slowly. Film left in a camera and subjected to repeated extremes of temperature (particularly very hot temperatures) will become deranged and show casts. B&W film will lose effective film speed. I don't get in a sweat about it.