Last week, I had a flat tire on my bicycle. I forgot about it until I wanted to run an errand a couple of days later, and then of course I couldn't run the errand. I took my bike to a shop, which might seem kind of pathetic rather than changing my own tires. However, it was a good thing I did--the welds for the struts which hold the back wheel onto the frame had almost rusted out.
So today I have nice solid welds painted to match the bike. It cost $80 (mostly for the welds, but I also got a new tire and inner tube).
It could have been worse--I'm a very cautious cyclist, but the welds could have failed at some awful moment in traffic. At best, it would have been much harder to get my bike to the shop if it had been in pieces.