I go through about 2 sets a year....and I don't even use them full time. My friend uses them full time in his Trooper and his lasted 2 years.

However, I retrofitted some xenon bulbs in my Hella Micro DEs that I run in place of my OEM circular lights, and I run those full time as headlights, and I go through a new set once every 3 years, literally. So, go figure.

H4 9003 is the type of head light connection....there are a few different types.