I've noticed that my weapon and armor durability has remained at max throughout my play time. Are they damaged through use as well as by death after level 10, or just from dying?
After reaching level 10 your items will lose 10% of max durability with each death,items will also lose durability during combat,and not just by taking damage also by dealing it(with every successful spell/attack),also just by attacking other parts of your gear will still suffer durability.
Note that durability is lost very slowly,probably increased with levels of gear/enemies.
Not sure why people say items don't suffer durability,i can't seem to find any durability changes in changelog also on diablo 3 forum someone confirmed durability loss(5 hours ago).
It might be bugged or unbalanced but rest assured it will be implemented since durability system is very good way for players to spend their money and blizzard knows it.
Out of curiosity, I went to Act IV Quest 1, my usual fun grounds, and repaired up: http://i.imgur.com/d6DWJ.jpg
Then I went to play with Iskatu's minions: http://i.imgur.com/SDvaW.png
Though it's very slow (the second image was after some five minutes of letting his minions wail on me while Galvanized Ward healed me back up), you definitely appear to take a small amount of 'stress damage' to equipment as you go. It seems to be related more to the number of hits you take than the damage you take, as these minions are pinging me for 15 a hit versus taking multiple and frequent 4k+ hits in Hell/Nightmare.
Curiously, stress damage also appears to damage your items evenly - no one item took more than two points of durability loss until all others had taken at least one.