Player Guide > Core
What can decay, what locking does, and why decay can affect perks.
Decay can happen when a skill gains a rank while your total ranks from skills are at the 400 skill limit. Languages do not count toward this limit.
The decay pool contains other skills that count toward the 400-rank limit, are not locked, are not the skill currently gaining XP, and have rank greater than 0.
LOCKED excludes a skill from the random decay pool. UNLOCKED means it can be selected if otherwise eligible. N/A means the skill does not count toward the 400-rank limit, so it cannot use the decay lock button.
If you are already at the limit and no other eligible skill can decay, that skill cannot gain XP from normal skill XP rewards in this circumstance.
After decay, perks tied to that skill are checked. If you no longer meet a perk's requirements, the perk is reduced to your effective level and SP is returned for removed levels.
Only other unlocked skills that count toward the 400-rank limit and have rank greater than 0.
The skill is excluded from the random decay pool.
Decay can make you fail a skill requirement, causing an automatic perk level refund.