..... or else it will bite you on the arse.
I had a chain snap on me the other day. Fortunately I was only a 5 minute walk from home. It could have been a lot further. I was also fortunate in that I wasn't honking up hill on the way to work or standing out of the saddle accelerating like a mad thing. If I had been, the sudden loss of resistance could well have resulted in a VERY painful manbits/ stem or top tube interface. That doesn't bear thinking about!
Anyhoo, on examining the chain I found that my maintenance had been somewhat lacking. I had been religiously cleaning and oiling the chain but, my inspection of its integrity was somewhat flawed. I had been suffering a slightly sticky link section which had responded to WD40 application, lateral pressure to loosen the links and much manipulation after soaking in oil. I thought this had solved it. What I didn't realise was that although the side plates had freed up, the rollers on the affected link were seized. Look at the profile of the rollers on this section of chain-
See how they have worn away and deformed.
In this image you can see a small stub of metal protruding beyond the side plate. This is part of the roller also-
Look after your kit folks, then, once youv'e done that, look after it again- just to be safe.