This is what I found on Durability and Self Repair.
It is OSI brand, but its a good start. Only Kane, or Dante, can let us know if they have changed any of these factors.
==Understanding Durability==
An items durability is comprised of two parts: the current durability, and the maximum durability, both of which are values in the range of 0-255.
The Current Durability on an item is decreased through hitting monsters, animals, or other players, as in the case of weapons...
Or through being hit by monsters, animals, or other players, as in the case of armor and shields.
==Self Repair==
When an item takes damage, the Self Repair property adds durability equal to its intensity (so SR 1 would add one point, SR 5 would add 5 points.)
It then sets a timer, and Self Repair doesn't go off again on that item for 60 seconds, even if the item gets damaged again. (Note) the example doesn't specifically say its always 60 seconds, it merely states the number given above as an example.
The green text above is probably what is tripping up most people. Now, with that explanation, you might understand why you are having a hard time gaining points back. Fight critters, that can only deal one damage to your equipment, in short burst, would be my suggestion. Its ether that or use a repair deed, and fortifying powder to compensate.
--Sturger, of Skara Brea, reporter at large, EVO-Herald--