I am think of upgrading the lighting in grandma's basement to linear fluorescent lighting. I already replaced one of the screwbase light fixtures with a twin lamp F40T12 fixture a few years ago when she got her new washer and dryer. There were originally five screwbase fixtures when the house was built (four in the basement and one at the top of the basement stairs. The lights are on a single light switch circuit but are controlled by a pair of three way switches (one at the top of the stairs and one at the bulkhead entrance). I am thinking of replacing the remaining three screwbase light fixtures in the basement with twin lamp F32T8 fixtures but I do not want to overload the switch. If it might overload the switch, I may install single lamp F32T8 fixtures. I might also install F40T12 fixtures due to the lower cost of the fixtures. The T12 lamps do not seem to be in short supply as I just bought a box of 10 Phillips Alto F40T12 lamps at Home Depot at $19.97, which is cheap. It was either $10 for a package of 2 bulbs or a box of 10 for $19.97.
I might also replace the light at the top of the stairs with a 2 foot single lamp T12 fixture. -- I've experienced ImOn (when they were McLeod USA), Mediacom, Comcast, and Time Warner. They are much better than broadcast TV.
The electrical draw of the fluorescent fixture is less than the screwbase fixture for the same light intensity, so you are lowering the load if anything. Personally, I would not change out the fixture at the top of the stairs for safety reasons. I would want that light bulb to turn on instantly so that I could go down the stairs safely. A fluorescent fixture sometimes has a bit of flicker and a pause before the light is on. JMO.