You might want to consider knee wraps instead of knee sleeves. There are far more adjustable. I wear 7 millimeters sleeves to lift but I would not want to wear them all day.
After reading through this thread, does anyone have a suggestion that would put no pressure on my kneecaps? I've tried the ones with the kneecap cutout, but can't get most of those to stay in place. I've had trouble with some of them bunching behind my knees as well, and man can the rub you raw!
I have seen some advertised on TV. Copper something, with Bret Favre. Are they worth it?? Also, If wearing a knee sleeve with long johns, should you wear it under or over the long johns?