Alter Aeon FAQ (Frequently Asked Questions)

FAQ 10.4 - Why can't I maintain <your favorite spell name here>?

Because typically, only the weakest and longest lasting spells can
be maintained.  There are very few spells that are worthwhile to
maintain, most of them being for detection or a small amount of
protection.  Larger spells such as strength and sanctuary simply
cannot be maintained - the cost is too great.