Mending bills:
Weapon: 167 work
Apparel: 167 work
Armour: 1000 work

Note this applies to all armour, from wood armour to cataphract armour. I believe this to be a mistype and should be 167 or perhaps 200.

To put it into perspective, 1000 work on a level 15 crafter with no inhibitions and a 112% workspeed from two tool cabinets takes over a day of uninterrupted work.
If you abandon the the work, you lose all progress.