Voltage in a fluorescent light bulb?
The normal aging process results from inert gas contamination from electrode wear which causes current to increase above a shutdown threshold to prevent excess power dissipation.

Most of the aging occurs during cold start if cycled many times per day in 4' linear tubes rated for 30khr which can last 50khr  if left on all the time.

Small embedded CFL lamp failures are subject to design variations and process quality and may fail from active ballast failures.