On 10/2/13, I installed a VL F15T8 Criticolor lamp over my computer. It goes about 10 hours per day. Today, it went EOL. I guess VL is not a premium brand as I thought. Granted, this lamp went about 14,600 hours and the rated avg life for a GE, Sylvania or Philips lamp of the same type is 7500. My guess is the long hours per start lengthened it's life.