Anyway to tell how old a VHO bulb is??

[SunnyX]

I ask because my newer VHO's got mixed in with my old used VHO's this summer while I was remodeling the basement.

I know at least one was never used and another was used for only 1 month. Its that time of year and I need to replace all bulbs but dont want to buy any extra if I dont have to.

[J-Burns]

I don't think so unless maybe a serial number and contact manufacture. Also as you probably known if bulbs are dark on ends they are near end of life.