Another pair of too short leggings with holes in both knees.This is the work in progress, the paper is my pattern for figuring out lengths and positioning.
I cut long strips from an old T-shirt and overlocked both edges with a rolled hem on the overlock machine using contrasting thread. These I cut into smaller strips which I sandwiched between two layers of fabric.
This is how I sew the patches on the knees. I use a sleeve board to pin the patch in place really well, then I turn the pants inside out and scrunch down from the waist to get at the knees.
Here is the finished product: