I have an overhead halogen fixture in the home office. It uses one of
those 300W double-ended halogen bulbs (118 mm).

I've had the fixture for a many years and have replaced the bulb 2-3
times. I never noticed that it got dimmer before it burned out. The past
few months, the light in that room has seemed dimmer. I thought it was
just my old eyes. But this morning the bulb burned out and I replaced
it. Now the room is bright like it used to be.

Do halogen bulbs dim with age?