has anyone here had luck reinforcing the seats of their pants? i wear through pants at a ridiculous rate and am wondering if it's possible to slow it down a bit. i tried an iron-on patch and it worked fine on the butt (one place where my pants wear), but not in the crotch (the other place they wear).
or, are there pants with double-layered seats?

Have you isolated exactly the point that is rubbing? If, for example, I discovered that my pants were rubbing against the bolt attaching the saddle to the seatpost. I covered the bolt with duct tape, and that alleviated it until I coud figure out a more elegant fix.

BDUs have double layer seats.

The proper protocol- buy some pants. Ride bike with pants until the seat wears out. Cut pants down into shants, sew up the hems, and use the perfectly color and wear-matched leftover material to sew up the seat. Save extra material for future repairs as needed. I'm currently wearing a pair that's on their third seat.

Iron on patches probably will not stand up without additional sewing around the edges.

I also second getting a smooth saddle- extra stiching/seams/perforation on the saddle wears out pants much more quickly.

Purchase a pair of cycling specific pants or shorts. Either road or MTB versions.
These take forever to wear out.

Agreed with the above.. If it not just a ride about town , expect the chaffing to that makes your rear end hurt to also tear up your clothes. Jeans might last a little longer but I doubt it. Bike specific shorts will protect both your rear and your pants. I just changed into street clothes when I got to my destination.