The 4-foot ceiling mounted flourescent light above the kitchen sink would stop coming on reliably for a few months. I would leave the switch on and eventually it would come on some time later. I had changed the F40 tube before so thought perhaps it might be the ballast instead. Went to Lowes and bought a replacement LED 4-foot light for $35 minus coupons and replaced it this weekend.
The first thing I noticed was the old fixture's ballast was too hot to the touch after turning it off. Not sure if that is normal, but I didn't like the idea of it burning up and causing a fire. The next thing I noticed is how much brighter the LED light is compared to the old one. It is supposed to be equivalent to the old one but seems much brighter. I also bought an LED 40 watt equivalent bulb for my desk lamp and that one seems the same as the old one.