Stupid question about t5's

[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?