an original lamp (original brand name of the tv) can be "alive" there for some years. if you want to buy a tv an suspect that the one is good or not just turn around that area one or a couple of weeks if still working with a great bright and crispy color is good symptom> (some re-manufacture lamps just work a couple of hours even new)
The lamp's life is a question mark in this technology (optimistic ingeniers (brands) count these hours as 1, 2 ,3, (thousand hours) (actually some manufactures count the time ""it is a simple timer the microprocessor can manage pretty well, but is not the mean of a good o bad lamp""
but i recommend my customers to have a spare lamp (just in case you are watching a beatles show) and blowns, you have it in the garage and (consulting the user manual) you change it a as regular bulb in your house.
But the lamp life "and this is the tip": (only two states)
- the picture tends to look dark or dimm (is logical because the high intensity the lamp works tends to create a tiny black surface on the heater and tends to consume more current and the answer is a dark picture as i told you already.
- the lamp blown (of course the tv cannot work and the LED "lamp" turns on or keep steady on the front panel with a complete dark screen.