Stupid question about t5's

[sharuq1]

I know this is a really dumb question, but my brain isn't working properly (that's my story and I'm sticking to it) :

How long can you run your t5 bulbs (normal usage for a reef tank, in say a Tek fixture-stock not overdriven to heck and back) before you need to replace them? I have heard everything from 6 months to two years and this seems like the best place to get that info.

Thanks all.

[jasond]

From what I have read, I plan to change mine around the 10-12 month mark. Totally necessary? Maybe not, but you will get the most from the lights that way I figure. Plus the price of bulbs arent too* bad. You could always do one at a time over say a month till they are all new.

HTH!

[Myka]

I change mine at 8 months, although from my understanding they are ok to go 12 months. I'd rather be safe than sorry...newer are always better.

[andresont]

Those who sell T5's claims that white bulbs run 24 month blue/actinics are 18 month.
However if you read German forums they change every 6 month.
So i guess 10-12 month is OK, say every Boxing Day.
But these are only like $24 (in my case), so if one wants to change earlier to get most out of the bulb then sure why not?