Story problem as it were. Got a call today that a client with less than one month old 40 watt 48" T-10 Chroma 950 lamps already had almost half of them bad. They sent back the bad ones and they had characteristic bad lamp brown/black ends on one side of the lamp. Not extreme dark and fairly wide in darkened end, but not un-normal as it were to see on a bad lamp. Main problem is that these lamps are less than a month old. The customer also noted in also sending back a half case of bad original lamps, that their 40 watt 48" T-12 Cool White lamps they used to use in the fixtures didn’t seem to have these lamp life problems. The T-12 lamps on the other hand seemed to have the same above brown/black ends on them, but again did not in a noticeable way seem to suffer from an overt short lamp life. In further refining the information about the place the lamps were installed, it was stated that the lamps are not switched on and off much and in fact, it’s thought that they are normally on. Also that the lighting fixtures that the lamps are in are surmised to be in decently old drop ceiling fixtures. These are not new lighting fixtures and will no doubt have normal magnetic ballasts designed for a 40w lamp. Main question by the customer is why the T-12 lamps seem to last just fine but the T-10 lamps died out within a month? I'm fairly certain of the answers to this question.. have a hypothesis at least and am waiting on more conformation from the lamp manufacturers and from an electrician. Question is more one of what I'm suspecting and why?