Notice they recommend replacing them each year! Halogens do dim over time and replacing them each year would avoid that and make it very unlikely you will have one burn out in use.

http://www.sylvania.com/ConsumerProd...skedQuestions/

Most of us can't be bothered or are too cheap to do that though. But if you want to maintain a vehicle very well you may choose to do that along with changing fluids and such at recommended intervals. I think the 150 hr life sounds way off.......probably get at least 2 yrs out of them using them more than the average driver. But if you think of the money spent on gas/insurance/etc./yr..new halogen bulbs a year aren't that bad of an expense. Most of the other bulbs are available in LL (Long Life) versions..aren't too much..and spares can be kept in the vehicle along with the few tools needed to change them.

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JBA s.s. headers&exhaust, K&N cold air intake, Bosch Iridium Plus 4 plugs, Royal Purple in motor, 5spd & diff.,Superchips programmer, axle girdle. Also have but yet to install KYB Gas-A-Just shocks and Belltech sway bars.