So.. We all know this mod is OP as all heck.. Once you get an ability you are set and you can become quite powerful in very little time if you set up a mob grinder. So... Id recommend making abilities toggable and, when on, consume EXP.

No cost for learning them, but to have them on. 100 exp per minute/per power

So, the more buffs on, the more the exp consumption per minute, that way you can be all powerfull all the time unless you have limited exp.

This can be a toggable hard mode, for those servers when balance is important.

Thanks in advance

Slightly related to #157.