I often find holes wear in my jeans between the legs, so I patch them with fabric on the inside and lots of rows of zig-zag sewing.
It’s not a very visible spot so it does not have to be perfect, but it definitely increases the useable life of the jeans considerably.
I’m currently working on patching a pair by hand and it takes forever. I’ve also stabbed myself several times but that’s just how it goes haha