Ok, I actually do know what causes equipment wear in Dark Souls. What I actually mean is a bit more specific.
Note: Before I start, I don't know the actual figures, but I do know there is a difference. However, the question isn't about those details (though it wouldn't hurt to include them in your answer).
So: when you hit an enemy, it does an amount of damage (or wear) to your equipment. Let's say it's a 1:1 - 1 hit = 1 point of equipment damage. However when you hit a wall or other object, it does more. Let's say it's a 1:2 - 1 hit = 2 points of equipment damage.
Now, there are a couple of situations here that I am uncertain of, and my only previous knowledge comes from the word of a friend, with no real backup evidence - I just went with it.
When you hit an enemy in a tight corridor, your weapon can either 1. pass through the wall (leaving a trail of sparks), or 2. hit it and rebound, at the same time it hits the enemy hitbox.
Your weapon passes through the wall (with a trial of sparks and hit sound effects) and hits the enemy - does it count as hitting the wall, and how much equipment damage is caused?
Your weapon hits the wall and bounces off (with a resounding ding) but still causes damage to the enemy - does it count as hitting the wall, and how much equipment damage is caused?
The last point I wanted to ask is does this apply to breakable props as well (I.e. Barrels and furniture etc.) or should I instead just roll through it all?