If you have a kid that crawls around a lot while playing, it’s a lost cause. I’ve tried every type and brand for my daughter- she can wear through the knees in days. She is 7. This has been happening for years. Her pajama pants have holes in the knees.
We set 1-2 pairs of leggings/pants aside for “church pants” - she’s not allowed to wear them except if we need to go somewhere nice and then she changes once home.
For some nicer, heavier pants I have learned to patch the knees to extend the use.