I use Sylvania Silverstar headlights as a inexpensive headlight upgrade. About one month ago both headlights went out at exactly the same time and of course in the middle of nowhere. I thought it odd that the both went at the same time so I called Sylvania to see if they had any similiar reports. What I did not know is that the Silverstars have a life of 8-12 months accordind to Sylvania. And they have had cases reported similiar to mine. So I guess the word is to replace them every 8 months. According to them the Ultra Silverstars have improved lifetimes of 12-15 months.