How often should it be changed? What happens if you don't? How do you do it? I just bought one.

i usuall chang mine ever other oil change. if you dont change it, it will get dirtier and dirter and possibly clogged. and also the dirter it gets the less amount of fuel can pass through it.

Not changing the fuel filter also affects your fuel mileage and power. I'm noticing it on mine after 11,500 miles, and started noticing it about 10,000 miles. My air filter is getting clogged, too. These turbo diesels sure pump a lot of air!

If you go to Cummins website they suggest 15000 miles...of course they also say change the oil every 15000 miles. I change my oil every 6000 miles.....and then I change the fuel filter every 12000 miles (every other oil change) As far as our trucks...changing it is quite easy. Looking at the right side of the valve cover you will see an aluminum canister where the fuel lines (under the oil check stick and behind the intercooler piping). It has a black cover with vanes and an attachment for a socket..I believe 1-1/8". Just back the cover off and remove the O-ring on the cover, pull the filter out, put your new filter in, put the new O-ring on (should be with the filter) the cover and tighten down. Then turn the key to "On" but don't start the truck. Wait 25 seconds and try to start it. Should start the first time. The fuel system is self priming, takes all the hard work out. If it doesn't start turn the key "Off", wait a couple and then turn it on and repeat the 25 second wait. The owners manual has diagrams and the procedure too. I would post pics, but my brother has my digital for the holidays.