Best reinforced hiking pants for the money that I've found are "5.11" brand nylon canvas pants. They have a double seat and knees. The knees have inside vertical "pocket" openings to insert 5.11s optional 1/8" thick neoprene knee pads. Great for rock scrambling. The price is about $50. These are TOUGH pants.

The company makes "tactical" clothing for law enforcement agencies but all the stuff I've had from them is top quality.
These particular pants come in 100% nylon or 100% cotton.
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"There are no comfortable backpacks. Some are just less uncomfortable than others."