Actually I agree, Staff of Magus should apply a durability loss to the staff like other weapons gets worn by use
I'd actually take it to the point of applying durability damage to the staff for all casted spells and summons damage (or make containers/doors immune to damage caused by summons).
Why? You can still cast magic without a staff, and unless your staff comes with a INT bonus it doesn't seem to boost your spellcasting in any way. Heck, characters don't even use their staves in the spellcasting animation, Staff of Magus excluded. And seeing as how swinging your staff or using Staff of Magus is usually the equivalent of throwing away AP (unless you're using it for an elemental effect), all you'd be doing is depriving spellcasters of the passive bonuses that come with equipping the staff.
Lowering staff durability when using Staff of Magnus is a fair and logical fix to door and chest breaking unbalance, but it doesn't make sense for the rest of spellcasting at all. And I am *not* a fan of the idea of making staves a prerequisite for spellcasting solely to make lockpicking pertinent.
The point is spellcasting allows players to trivialize the Lockpicking skill and get around durability loss penalty when blasting past locks.
So, either make locked doors and containers immune to magic, or come up with a penalty that is on the same level of durability loss. You can require a weapon be equipped to cast a spell, it doesn't have to be a staff, and then have that weapon take durability damage.
You are talking about the *feature* that simply takes up on slot for a repair hammer and has no further influence on the game?
Using that repair hammer takes points in the Blacksmithing skill. That creates a cost to using it.
