Just think about this. Squats don't do ANYTHING beneficial for the menisci. Yes, toned leg muscles will help keep the knee functioning properly and help avoid injuries to your menisci. But as I said, the squats themselves aren't doing anything beneficial for them specifically. What they do is add the unnecessary risk of injury, especially if squatting technique is bad. But even with proper form, people have torn their meniscus while squatting. Given that there are other safer, just as effective exercises, my old wife asks me why I would risk doing them? No good answer, so I don't do them and use the wall sit quad exercise instead. The knee is a joint, and like any other type of joint, human or mechanical, it will wear with time and stress. Why help it along.