One of the simple pleasures of riding is working on the bike. I had a couple of items to work on: the bottom-bracket/crankset area was clunking a little, and I had an new derailleur to install. Went ahead and replaced the chain while I was in the neighborhood. Started with the derailleur. The key difference between this one and the previous is the bearings on the pulleys - I'm hoping for better weather resistance. Got it installed and adjusted easily enough. Used a new cable.
The tricky bit was the clunking in the crankset area. Taking the bottom bracket out showed some thread-loss on the drive-train side - on the outer part of the bottom bracket. I'm not sure how the threads were lost - but, I'm now in the market for a replacement.