As you said, there can be a whole bunch of reasons for the "check engine" light to come on. Some vehicles have it pre-programmed to come on at a specific mileage to induce you to take the vehicle to a mechanic for scheduled maintenance of things like the timing belt or pollution-control components. If the light came on at some exact mileage figure, like 60000, then I'd say there's probably minimal hurry in getting it serviced. Replacing a timing belt is crucial, since a belt failure can ruin the engine, but I've successfully postponed replacement past double the recommended milage. OTOH, if the light came on because of low oil pressure, then you could be trashing your engine and not have another clue. (Why they don't include a USB port and some nice GUI program to explain exactly what's up with your car is an unfortunate mystery. I'd buy a car that did).
