My kitchen had 8 4' fluorescent fixtures in the kitchen when I moved in, and a couple of them flickered. I didn't bother check ballasts or bulbs and instead I've replaced them with the Hue strips + extenders. I've seen ballast replacements for LED tubes, but at the time did not see Hue compatible so I went with the strips.

Anyone that says they like CFL has to be trolling. Any other answer is just inconceivable to me.

I didn’t realize it was so controversial. Indeed, I have a set of CFL from around 2010 that have about 30 second warm up to full brightness; they look just right behind their lamp shades. I tried replacing these once with LED and the light kind of pierced through the shades and looked harsh.