In 4, Wayne Boatwright
wrote in part:

Also very good information. Since I'm faced with replacing 12 recessed
cans, I may give those less expensive screw-in CFLs a try first. I'm not
looking forward to the expense and effort required to replace those cans,
especially since I have no access from above.

One more thing to watch out for when using CFLs in recessed cans: Heat.

CFLs are paradoxically more efficient at producing non-radiant heat than
incandescents, despite also being more efficient at producing light.
(What CFLs produce less of is infrared - becomes heat, but mostly outside
the fixture.)

CFLs don't withstand heat as well as incandescents do. In screw-base
ones, their ballast electronics can get cooked all too easily.

If you start having screw-base CFLs not specifically rated for
recessed ceiling fixtures dying young, it's probably another reason to
get fixtures that have ballasts and take ballastless CFLs.

- Don Klipstein )