I've been trying to get a clear answer to that one for the last couple of years, but every time I ask Panasonic or Infocus about the high cost of replacement bulbs I get some mumbo-jumbo about the high tolerances or exotic materials that go inside—or more commonly no response at all. It's been bugging me lately because my beloved Panasonic AE-900U is getting dim. (And has a wicked fan rattle, too, but that's probably both fixable and the fault of Porter's disgusting shedding, not a failure endemic to the model.) I priced out new bulbs and they're all about $300-400, depending on the source. What is a real pisser is that I could buy a used AE-900U on eBay for around the same price, making it clear that the only thing of real value inside a projector is a fresh, new bulb. It's got to be a racket, right? I understand that those lamps need to throw out a ton of lumens, but even if they're filled with strange metals and inert gasses, hundreds of dollars for a bulb seems nutso to me. Then again, I'd feel a lot better about paying for a new bulb if I were wrong, so if you've got some science to drop on me I'd love to hear it.