Well, I don't think it should be mandatory, but I've switched all but one light fixture to compact fluorescents and my energy bill has decreased by about 15%. FWIW.
Many people won't like the 20sec to 30sec warm-up time though.
I would change over more of mine ( primary reasons: longer life, long-term $ savings), but they cannot be used with electronic timers, or photoelectric switches, or dimmer switches. Most every light in/on my house is in one of those categories. Where I can use florescent bulbs, they were changed over years ago.
Our electric utility was offering a rebate on CFLs which reduced the coat of the 60watt equivalent bulb to $0.25 so I stocked up. I changed the bulbs in the garage door opener and found the bulbs would not start in cold weather. I changed the bulbs in the basement which has a motion sensor switch and was going through bulbs like salt pork thru a goose until I figured out the CFLs don't like solid state switches. I confirmed that with the lamps in the rooms that had X-10 remote control light switches. Average CFL life was about a month before failure and sometimes less. At times failure was preceded by an amusing "strobe" effect which tended to drive people out of the room.
What few bulbs I have left are installed in closet fixtures with a pull chain switch. My wife observed that who ever rated those 15watt bulbs equivalent to a 60watt incandescent in illumination was being "very optimistic", and I have to agree.
All in all, I would say that CFL are not ready for prime time.
Regards,
GtG