Yesterday I went to the gym and did thirty minutes on a stationary bike. My knee acted up, made it painful, but not so bad that I had to slow my pace. I gradually went from level 4 to level 8, doing the random hill program, and when I got off the bike I did not limp.
I consider it a positive outcome.
So today I got my bike carrier out to put on my car. I was unable to attach it correctly, so I had the sense to take it to a bike shop and let them do it. Then I went home, put the bike on the rack, and went right back to the bike shop. The bike is getting a tuneup! Plus a new rear tire and a few other sundry parts. At last!
What I love about bike shops, the real types that is, is that the workers there never seem to suggest that one might get a new bike. If you bring a bike in for repair then they will repair it and not even stop to glance at a newer better bike that you might want. I think they know, because they are cyclists too, that 1) bikes essentially can last forever and 2) we form deep attachments and 3) when we're ready for a new one we'll tell them.
I say this about "real" bike shops because I've been in some where the owner and workers don't even ride bikes and they certainly don't repair them. My advice: do not buy a bike there. This shop where I went brags that everyone who works there rides. For whatever reason this makes them nice people, too.