- Make it painless - Make it relevant - Make it interesting/engaging
To be relevant and engaging a system for siphoning players resources must, by the very nature of what it's meant to do, be an inconvenience when ignored.
If durability maintenance is made to require no effort, and cause no frustration, it might as well not exist. It doesn't really matter if the enemies drop 10% less gold, or if I spend 10% of the gold on repairs when I get back to town. The end result is I have 10% less gold.
As far as the engaging parts such a system can have, I already made a suggestion which retains all of them with none of the pains of maintenance.
-A way to open containers you can't lockpick, with a cost attached to it(crowbars instead of spares). -The interesting part of weapons being broken mid-combat(having to re-equip).
