* Magery and Necromancy spells require 20 skill points above the minimum requirement to be cast 50% of the time, and 40 skill points above the minimum requirement to be cast 100% of the time.
* Chivlary spells requires 25 skill points above the minimum requirement to be cast 50% of the time, and 50 skill points above the minimum requirement to be cast 100% of the time.
* Bushido, Ninjitsu, and Spellweaving spells require 12.5 skill points above the minimum requirement to be cast 50% of the time, and 37.5 skill spoints above the minimum requirement to be cast 100% of the time.
* All minimum requirements except for magery are listed in game. Magery minimum requirements can be found on UO.com:
http://guide.uo.com/magic.html