I too have had knee issues. They seemed to get worse after my lumbar fusion surgery. Though they feel better now that I have lots 30 lbs. I got a hot tub to put on the back deck and am amazed how much better that makes me feel. I sit in that 104 deg water with those jets working my old tired muscles and wow after 20 min I am loose as a noodle.
I agree with Woody live now while you can for no one knows what's to come. If you cross the things off your bucket list as you go you will get most of them done before it's too late. I have one of those living wills so no hoses and machines for me!!