I was at the hairdresser today, and he was telling me about another customer who had had a few days in Dublin. She'd gone out for dinner in a smart restaurant and had been thrilled to see Bono at another table with several other people. She's a huge U2 fan and worships Bono. She was too chicken to go and speak to him, but when she went outside for a cig, she got chatting to one of the people from his table and told him how much of a fan she was. The bloke she was chatting to told her to go and say hello, saying Bono wouldn't have a problem with it and would be quite happy to say hello, but she didn't dare. When she'd finished her meal she asked for the bill, and the waiter said "no bill, Madam, Mr Springsteen has taken care of that for you." 
That's a great story, even if it is a bit FOAF so likely embellished and/or exaggerated (or just plain made up!)
Taking about the B&M Cyo, assuming that it uses a capacitor, which seems likely, then it's effective lifetime is more about duration than usage.
As Kim said, it'll last much the same time, regardless of how much you use it. For a large capacitance device (which it will need to be), it'll most likely be an electrolytic, and whilst they tend to age more than other, smaller capacitance capacitors, it'll probably have a lifetime of a decade or more (this all assumes it's being used within it's spec).
We have electrolytic capacitors on spacecraft that have been in flight for 12 years, and the instruments were built before then, and the space industry is notoriously conservative in what components they use.
Something else on the light will probably break or fail before the capacitor does.
