T5 bulb question

I have a nova extreme T5 light setup and i was wondering how often the bulbs need to be replaced. I've had these for coming up on a year next month. Does the quality of the lighting decrease over time or does it just burn out one day?

 

The quality of light decreases. I believe it begins to put out less light and your color spectrum begins to faulter. This is what I've heard.. .Many people on here are light experts and hopefully will back this up If not... that means I have some more reading to do I have no Idea how long T5s last, I've heard just over a year, but i run MH for 9 months and replace.

 

Yes, Froc3, It does start to put out less light and the spectrum does shift. I have done alot of reading trying to figure out if PCs or T5s are better (if you're read my recent threads)
In my experience, The light dims so gradually that you don't even notice.
One day you'll change the bulbs and they'll be so bright you'll be like HOLY!

I've been in the position of putting 2 year old Vho's on just to try to maintain life while I sent my other ballasts out to be rebuilt. They WILL stay lit but not as bright as you want them to be.
Metal Halides on the other hand, the filament turns black.
One year, change'm

 

T5 bulbs do last longer than metal halide bulbs and pc and the spectrum holds better also. But I would replace them about once a year. It is best to not do it all at once, so replace 1 or two bulbs, wait a few weeks then do the other ones, that way the corals won't be light shocked.

 

awesome, thanks guys