Fuel Filter

How long do they usually last?

replace every 30k miles. some places recommend replacing as often as the air filter and pcv, like every 12k miles.

Its this difficult?

not really, depends on condition of car and when it was last changed. mainly just relieve the pressure in the fuel system by removing the gas cap and relieving pressure at the shrader valve, then loosen the clamp holding the fuel filter, disconnect it, put new one in, clamp it down, and your done.