In article , Blue wrote:
I talked with a guy in a large department store replacing flourescent bulbs
about the 1-2 problem. He said a failing bulb also extinguished the good
bulb but his procedure was to rather than try to find the bad bulb to simply
replace them both as they are cheap and aged at the same rate so that the
"good" bulb was nearly aged out anyway.

This is mainly for 2-foot and longer fluorescents, as well as some
ballastless compact fluorescents in 2-bulb fixtures that have separate
2-bulb ballasts somewhere in the fixture (not the usual screw-base compact
fluorescents).

- Don Klipstein )