My knees don't get really bad unless I try to run, or jump off of something, or if I have to stand for a very long time. Biking is mostly pretty easy on my knees as long as I don't push too hard. I just have to remember to spin instead of mash, which can be difficult because I've always been more of a masher. Also, before I moved here and started walking everywhere, my knees were actually worse. When I first moved here I was taking a prescription daily to dull the pain, and I could still only walk a mile or two before hurting. Biking was only a little better. But I guess all the walking I've done throughout the winter has strengthened my knees somehow, because now I can walk three or four times as far without feeling anything but a dull, subtle ache, which is more of a nuisance than a true pain. But running is a big no-no for me, not that I ever liked running anyway. And both of you, standing is the worst. In fact, I think my last job, where I would stand on concrete for 8+ hours ever day, is what screwed up my knees in the first place.