I wrote Sylvania re the early death of my Silverstars. Here is their reply:
Thank you for your web inquiry. Unfortunately, as with most high performance
products, there is a trade-off between the higher performance of the SilverStar
and its life hours. The shorter life span is directly related to the high
performance nature of the lamps. The blue absorption coating on the glass
contributes to the crisp, white light emitted but also contributes to its
decreased life. The SilverStar product works harder (not burns hotter, however)
to give the whiter, brighter light and this impacts its life hours. The life
expectancy of a SilverStar halogen light source is largely dependent on the
driver'* use of the lights, which will vary by season, time of day and number of
miles driven. We estimate the SilverStar halogen lights to have a life span of
up to one year under average driving conditions. The life of the SilverStar is
further decreased if being used in a day-time running light application.
So, they work great, cost a lot....and only are expected to last a year.
Y2K Midnight Blue SSEi
White Cathodes in Grille/ Blue Cathodes Under Seats