I sprained my left knee three times this year with the severity increasing with each time; I would say this is my weaker knee after years of basketball and running and other sports. I guess the sprain progressed and affected my technique as I tired in mid-afternoon. So I got a knee brace (Shock Doctor w/Bilateral Hinges) and skied Saturday (Montage, PA) and Monday (Blue Mtn, PA) with two different groups of friends. Knee felt fine and held up pretty well until mid-afternoon yesterday, so I ramped it back to easy green cruising until quitting time. I really didn't notice the brace at all when I was actively skiing but it was a little annoying on the lifts. My knee feels sore today, but no pain. After my big trip to Sunday River and Sugarloaf in January, I have a shorter trip to Killington in two weeks for which I want to maintain my ski fitness and be sure my knee will be more fully recovered and capable of several days skiing in a row.