Greywolf1: I've never tried to play a pure mage in Daggerfall - interesting idea. You would have to run away and rest a lot, I guess, and for quite a long time, I'm afraid.
Or, of course, you could use an exploit that I believe is the result of a miscoded ability.
If you take, at character creation, the "Spell Absorption" advantage, you will always absorb any spells that you cast (provided you have no other Spell Absorption effects active). This, in turn, means you can create an "Area at Range" spell that uses up almost all of your spell points, and use it constantly; as long as you are caught in the area of your own spell, you will absorb it and be able to cast it again; in the meantime, enemies nearby will be affected by the spell.
Aside from this exploit, the "Spell Absorption" advantage seems to be rather useless; it seems that you can never absorb spells cast by enemies of comparable level; it's as if the game has a check to prevent you from absorbing your own spells, but the programmers got the check backwards.
Other spell absorption effects don't have this behavior; items of "Spell Absorption" allow you to absorb both your own spells and enemy spells, but don't work 100%, while spells can be made to work 100%, but will be expensive to cast. Also note that other forms of spell absorption take precedence over the class advantage.
Yes, the developers messed up this aspect of character creation, but that's Daggerfall for you. It's not even close to the only game mechanic bug I've encountered. Don't trust that the game works correctly; actually *test* to make sure effects work as described. I've been instantly killed by an enemy's arrow having my weapon's enchantment; I've taken large damage from guards after using an artifact to boost my Strength to very high levels; and so on.
(By the way, is Illusion useful at all in Daggerfall, or is it so badly bugged to be worthless? I know the Charm spell is defective, as it doesn't work on non-hostile NPCs, which is the only time its effect would make any sense, but what about invisibility effects?)