Do T5 bulbs output fewer lumens as they age?

[dragon49]

I just replaced one of my T-5 bulbs that finally gave out.  It looks like the others are close to the end of life because the black area around one end is getting longer.  Other than this "dead zone," do the T5 lights output fewer lumens as they age?  Should I proactively replace them?

 

[Mr. Hill]

I think most lights do lose lumens as they age

 

[queequeg152]

yea they dim. if you have a pair of dark sunglasses or something like a welding helmet, its really easy to see.

 

[willard3]

Check where you purchased the lamps. They will have data on how the lumens decrease with age.
 
 
http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/t8/05-t8-lamp-life.asp

 

[Pfeffer]

Also note that not only the lumens decrease, also the color changes. This is not necesarrily a bad thing, the problem is that you don't know how it changes.

 

[dragon49]

yea they dim. if you have a pair of dark sunglasses or something like a welding helmet, its really easy to see.

Ty - With my good shades I can see a brightness difference between the fresh one and the other bulbs.   I'm about the change the others.