T5 lamp visibly dimmer

[E-A-G-L-E-S]

If one or two T5 lamps in a 6 lamp array is visibly dimmer than the same brand and type lamp, does that mean it is time to change it out? It is about 6months old @ ~10 hrs a day. This is my first go round with T5's.
TIA!

 

[rtparty]

Are the two on the same ballast? I would suspect ballast first and then the bulbs. Switch the bulbs around and see if problem follows the bulbs or is it a particular slot that is always dimmer.

 

[E-A-G-L-E-S]

Good idea...I hope it is just the lamp as I do not feel like changing out a ballast.