I have a lightbulb that was given to us by our power company, SDG&E, that were guaranteed for 25 years in 1985. It was never very bright, but is still working today. I have it in our closet now. Before, my youngest had it in her ceiling light because she never liked a very bright overhead light. She used a bedside lamp to read. When she moved out, I put a brighter light in her room and moved the bulb to our closet. Thought several times about getting rid of it - but just can't.