make sure your not screwing the bulb in to tight.... i forget the name of the gas that is put in the bulbs to stop the filiment from burning out. sometimes when screwing in to tight you can break the seal slightly and the gas slowly escapes and finaly burned out bulb. also make sure your lamp is plugged into a surge protector .. in older homes there can be micro power surges that can over heat the tungsten burn it out. i have had this happen so many times / also worked in a reptile shop and had bulbs returned all the time for the same reasons ... zoo med bulbs are bad for blowing out.. but they are awsome when you get a good batch