Leveling up with 255 unused perk points will cause the counter to roll back to zero and restart. The maximum value for unused perk points is 255, four more than required for every perk. One perk point is given to the character when the character's overall level increases. The perks are all detailed on the individual skill pages, along with their requirements. 180 skill perks are available, 251 if including all ranks for each perk. Each skill has its own associated perks, which can be unlocked when a character advances a level.
