at that point, make it be based in how long has it been since you used it in synced content.<that isn't PVP, VnC, Side content.>
since people can rust very easily.

(the largest issue the idea has is when is it considered an issue for the player to be accustomed to the job and move past the skill floor. <applies to both if the player can toggle it or not, or with restrictions> cause if it exists, players may come to expect it.
And those who are paper thin, and can't understand will cause a fuss over it)