As promised, I posted a queery to my associates on the theatre crafts
listserv on the question of how long quartz/hallogen lamps would need to
run full to restore the regenerative cycle.

No one had an answer but there were lots of guesses. The concensus seems
to be that a very short duration at full each week would do the trick
(about 15 minutes), but many pointed out that since lamp life is longer
anyway when less electricity is used, quartz lamps used at a dimmer level
may have very long life no matter what. Good point there.

Richard Finkelstein
Head of theatre design
U of Colorado at Denver
School of the Arts