Lower quality material such as bronze and especially copper is going to fall apart quickly if it takes a hit. Leather armor may as be civilian clothing for the good it's done me, as it crumbles as fast as a coat or robe under the punishment I usually put it through. Using lower quality armor as an outer ablative layer to extend the life of your good stuff does sound like a good idea.
However, In my experience armor skill appears to reduce the wear taken by armor and clothing in combat.
Here's an excerpt from a scuffle I had with a night troll about a week ago. The adventurer was at skilled armor user, and full plate is just leather armor that is actually acceptable armor made from metal.
The bleak freak gores you in the left upper leg, bruising the muscle through the Xfull iron plateX!
The bleak freak charges at you!
You are surprised by the ferocity of The bleak freak's onslaught!
The bleak freak collides with you!
You are knocked over!
After pulling a Sir Robin, replacing the armor, and getting that adventurer's armor skill up to talented, the rematch went a little better for me.
The bleak freak gores you in the left upper leg, bruising the muscle through the full iron plate!
The bleak freak attacks you but You jump away!
You attack the bleak freak but He jumps away!
You strike the bleak freak in the throat with your iron shield and the injured part is crushed!
The force bends the neck, tearing apart the skin and bruising the fat!
Never use the same move twice.
It makes sense taht someone experienced with wearing armor would be able to mitigate damage inflicted on their equipment, as much to keep themselves alive as to extend the service life of their equipment. If this is the case, then it would be a good idea to stick to lower quality armor until you've got a higher armor user skill. There's no point shelling out for steel armor right out of the gate it you're just going to dent it up while training on wildlife.