Usually takes 2-3+ stuck sheds before the tail tip really dies from lack of circulation, but like with humans, you cannot predict due to individual differences, & in ANY case, that skin left on the tail tip gets more stuck (harder to remove without damaging his skin) the longer you wait. The tail tip has a very tiny blood circulation to begin with...it doesn't take much to cause gangrene, and unfortunately that can also spread & further affect a snake's health. It's never a "good" thing, ok?