Chain trouble

I had the master link let go on my chain today on the way home. Weird. I've been told that those 2-parters don't re-use well, but the last one I had got reused at least a dozen times without trouble. This one had been taken off exactly once last time I cleaned the chain, and it came apart. As with last time (several years ago) it happened when downshifting.

No big deal, I carry a spare, I just walked back, picked up the chain, looked around a bit and found 1/2 of the master link (surprised I found that much, it was a gravel road), got out a new master link and remounted the chain. Back on the road in about 3 minutes.

I suppose I might think about picking up a Park Cyclone cleaner so I don't have to take the chain off the bike to clean it.