This is why I need a bicycle with a belt, rather than a chain. [See previous commentary about the Novara Gotham bike.] Or a "bike butler."
My shifting has been deteriorating recently, and occasionally the chain has been jumping cogs. It had been a month or maybe six weeks since I last cleaned the drivetrain. (I should do it every 2 weeks; the reality is more like every 2 months.) So I figured it was probably just gunked up; I lubed it in the morning, thinking that would tide me over 'til the weekend when I could do a cleaning/lube. Then in the afternoon I took a couple paper towels to wipe off the excess lube. If I had a bike butler, I'd expect him/her to have significantly higher standards.
Lo and behold, as I was wiping the chain with the towels, I encountered an obstruction - the chain was actually pretty much broken!
Yeah, I know! GROSS!!
As far as I know, this is a first. But it makes me a bit uneasy. How many times have I ridden up my hill in the afternoon with a faltering chain? How many "rabbit starts" have I done to beat the approaching traffic?!! I'm glad I discovered the problem under such favorable circumstances. And I'll try to make a practice of at least a quick check a little more frequently, going forward.
Chain and cassette have both been replaced. (Some people replace the chain 2 or 3 times a year; I try to make the chain and cassette last a year... and the crank rings are typically good for a couple of years.)