These pants with holes in their knees had been laying on the mending pile for weeks (if not months). I finally took the time to patch them. Once started, I figured that I could just as well spend some extra effort to make them a bit special.
The first pair got large embellished pads, sewn in both side seams. I opened up the side seams with the seam ripper, attached the knee pads, and resewed the seams. However, it turned out that resewing the double seam was quite tricky.
So for the second pair, I opened only the outer seam and appliqued some stars, Not just two to cover the holes, but a whole constellation of stars.
Done. It took a bit more time than I expected, but I like the result. Two cool pairs of pants for my tomboy.