Thin-Lite LED light fixture?

My biggest problem is that I have four twin fluorescent lights. Only one of the four gets used on a regular basis. They are ten years old and so far there are no failures. I can not justify replacement until there is at least a tube failure.

I was an early adopter for led and have been using them for 13 years.

I admit the idea of being able to dim the light would be an asset. Does this require rewiring the switch? Or is there some sort of control right on the fixture?