I have only changed a 65W tube to LED when I found no longer made 65W and the 58W tube needs the ballast changing. Since one end of the LED tube is a short circuit both ends should be wired in series so the tube can be put in either way around, this still means if a fluorescent tube is refitted there is 230 volt across the 10 volt heaters. It seems you can leave the ballast connected but the volt drop caused by leaving it in means the system is far worse lumen per watt wise than a fluorescent tube, so really the ballast does need removing.
The replacement tube was 24W and I thought that was far better than the 58W of a fluorescent until I found the lumen output also dropped from 5800 lumen to 2400 lumen, so the tube was giving out a lot less light. In a hall way where you want the length of the tube but not the output they work well, but in my kitchen the light levels were important that's why I fitted fluorescent in the first place. So to get same output I would need to convert to a twin tube fitting and the whole reason to change was I did not want to change fitting.
I have got away with the lower light output, but it's not ideal. After I looked at lumen per watt, and with a HF ballast and good quality tubes a fluorescent lamp is around 95 lumen per watt with LED at 100 lumen per watt, and the life is around the same and cost to replace a fluorescent is a lot lower than replacing a LED tube, you can get the ballast and the fluorescent tube for the price of the LED tube.
I have an 18W fluorescent tube at the top of my stairs, HF battery backed, fitted in 1992 renewed the tube in 2013 and it is left on a lot I would guess at least 8 hours a day, stair well in centre of house so winter the light is left on. With that sort of life, the battery has now gone but lamp still working, why use LED?
For the folded fluorescent tube used with CFL then the lumen and life output is much reduced and swapping for LED even when the LED is only 70 lumen per watt is a good move, the CFL was really a failure, so most if not all of mine are now swapped for LED. But with the tube the fluorescent lamp is still king, just fit a HF ballast and swap the tube every 10 years.
