When the pockets or belt loops rip away from jeans I make two small patches,  cut from an old pair of jeans. I put one on the inside and one under the pocket or belt loop. I zigzag the patches to the jeans at the same time and then sew the pocket or belt loop back down.

I try to match the patch to the shade of the jeans and I buy denim thread to make the patches blend in as much as possible.  It sure extends the life of the jeans.

I experimented with a new pair of jeans this week. I made a small patch and put it inside where the pocket is attached and just sewed around it with a straight stitch. That will give extra reinforcement for the pocket.  I hope it keeps the pocket from ripping.