These are the most durable pants I've ever worn.  I used to wear them daily for industrial HVAC and pipefitting work, and now I wear the same pairs for solar installation.  I've shred a few pairs of jeans crawling on asphalt shingles and abrasive concrete roof tiles putting in solar systems.  The denim literally falls apart.  The Dickies cotton duck pants don't even show signs of wear.  Completely durable.  They are cut on the slim side, so the advice others have given is true...if you're used to wearing a big pant like a Carhartt, you'll want to go a size up.