My thoughts is that in order to simulate some realism with defending a belt that's 24/7 and as highly regarded as the X-Treme championship belt, it should start at 12 hours, if no one has attacked that day. Then, if there's one attack, then that's a half-hour depletion. More, if several attacks happen in a one hour time frame. Because by getting their ass beat all the time, they shouldn't have the strength of a bull after each kick-out. Maybe after the first few attacks, but once you get to the, say, 10th attacker, you should be drained from all the abuse and kicking out. I would say "let's add a HP bar!" but people could just wait long enough based on the HP % and then get the last pin in.

But anyway, the time should decrease depending on how many people have attacked in a day. But it would never deplete further than an hour. Even if the person is the 23rd, the time wouldn't go lower.