About this permanency...I think that enchanting weapons/armor is supposed to wear off, just like other spells. Otherwise everyone would be carrying around enchanted weapons, and wizzies would stand by the font enchanting plain longswords, etc. There wouldn't be any non-magic weapons, and those should FAR outnumber magical weapons (which they hardly do, really). Besides, it wouldn't be fair for fighters to have the benefit of a permanently enchanted weapon...as discussed in another thread (which I can't remember the name of), spells are intended to be for wizards more than any other class. Therefore, since they have the spell, it is ok for them to have constantly enhanced armor/weapons...whereas for a fighter it wouldn't make as much sense.
Think about a world where everything was magical (as it would almost certainly be with permanent enchant weapon/armor spells). Nothing would be worth as much, since magical items would no longer be rare, and we don't want our precious magical hoards to be worthless, do we?
