Saeviomagy
Adventurer
... whose abilities are, as a general rule, less powerful than his own dailies.Don't worry about it - it's already taken care of in the rules. This is exactly the reason why you have a limited number of daily item power uses available per day (with additional uses per milestone). See page 226 of the PHB. An epic level character who simply carries around a bunch of Veteran's Armor is limiting what they can do with other, high level, magic items.
The simple solution is to disallow veteran's armor, because it is simply far too good.