Originally Posted by
miokomioko
They stop working at Rank-11.
From Rank-1 to Rank-10 (for crafters) they will scale from Craftmanship+6 to Craftmanship+12 and then the hidden bonus drops to 0. They are essentially awesome gloves for the first 10 ranks, then you gotta' find something better by 11. However, if you don't have anything better than the static Output/Control+1 that they will always have, by all means, keep 'em on. They are cheap as shit to repair via NPC too.
It's the same thing for gathering classes, just with Gathering instead of Craftsmanship.
I'm not sure of the exact numbers for war/mage disciplines...