Replace on hours, not on failure. What an aged lamp looks like and why the last hundred hours are the dangerous ones.
Every projector and most lamphouses keep an hour counter per lamp. The manufacturer's rated or warranted life is the replacement point. Running past it is not economical: light output has fallen 20–30% by the end of rated life, so you are paying full electricity for a dimmer picture, and the failure risk rises steeply.
Brightness drop that the projector's lamp-power compensation can no longer hide. Arc wander or flicker on screen. Longer or repeated strike attempts. Blackening of the quartz bulb around the anode, visible when the lamp is cold. Devitrification — a milky, frosted look on the quartz — which means the bulb wall is weakening.
A xenon short-arc lamp is filled to several atmospheres cold and much more when hot. As the quartz devitrifies and the electrodes erode, the bulb wall carries the same pressure with less strength. Most non-contained failures happen on lamps well past their hours. A burst inside the lamphouse can destroy the reflector, the UV filter and the blower — far more than the price of a lamp.
Keep one spare per wattage on site. Schedule replacement at 90–100% of warranty hours rather than waiting for a failure during a screening. Log the hours of each lamp removed; that log is also what you need for a warranty claim.
Send the part number or a photo of the label and your equipment model. We confirm fit and quote within 24 hours.