It’s too hot for jeans now, so I’m switching to cotton slacks/Dickie’s-ish pants. I love the flexibility and the nice circulation, but I rip these at the knee way too often. Plus, they pale in comparison to denim for protecting from shinners (a near-daily occurrence). What kind of material or type of pants provide a good medium? Flexibility, circulation, and somewhat tough? Can't afford much outside of the thrift store, though...