I failed to mention that I also installed SilverStar White Light halogens in my 01 GSXR1000 just a couple weeks after I installed them in my Hayabusa. So they're also heading into their 3rd season of use.
Any filament type bulb is susceptible to premature failure but I'm not finding these SilverStars prone to early failure with as many years and thousands of miles as I've already gotten from them.
Your bulb's connector should be making a tight fit to the halogen's terminals and the contacts should be clean. Likewise, the halogen's glass should never be handled with your fingers, as the oil from your fingers will cause excessive heating of the halogen which can result in premature failure. I always clean the halogen's glass with alcohol and a clean cloth prior to installing them just in case some idiot at the plant where they were packaged had previously handled the halogen by its glass.
Naturally, severe highway bumps, hard wheelie landings, poor physical connection or dirty electrical connection of the halogen's terminals will contribute to the halogen's premature demise as well.