Googled, couldn't find the answer.

If I lose durability on an item, then up it, will the durability reset?

I got some 40% chance guards, and wanted to ride them as long as possible.

Iirc they get random durability

When they get to 1 dura make a free here game and drop them

I remember i tried it before but the durability did not reset

Try it and let us know