So I replaced the halogen bulb in the retro headlight, which is really just one of these:

with the retro shell (black is available in Europe only, I guess) and it is not user-friendly. The whole lamp needs to be unhitched from the hub's wiring, then unscrewed from the clamp, and then the reflector glass and the unit need to be separated with brute strength and dexterity at exactly the same time to get to the bad bulb.

I guess the whole process would take around eight minutes, but in the dark by the side of the road? Maybe double that.

This is a bit of a rant, since I was angry about some near misses with cars not seeing me this morning after the bulb burned out, but some bike components really need to be easier to use and maintain. Usability should be a primary goal.

Anyhow, the bulb's back, and the light makes me happy again. Note to self that I should expect to replace it again in about 3 months.