I agree with a lot of the comments that LEDs are the future. On deep planted tanks you can get better penetration and don't have to worry about replacing bulbs every 6 months as mentioned.
I'm still testing this but am finding that par drop-off due to bulb fade can actually be significant over the 6 months. I'm guessing this is why I've been told a few times not to replace all bulbs in say a t5ho at once as the plants get a shock.
On the flip side here I find that LEDs for saltwater tanks are fairly well designed, for freshwater I'm not quite convinced. It's certainly been something on the planted side that has just taken off in the last few years and I still see lights very high in blue light / very little red being marketed for freshwater. As well as that the LEDs are much more expensive and I've found can have a shorter life if they get hot.
I run a quad t5ho and recently added an LED
strip light that I'm running with white channel only (blue channel off). In the end the bulb cost is just a bit much. If bulbs would last 12months wouldn't be so bad.