I am just getting into diesels and have found an 05 lly duramax for a great deal. After doing a little research, I see that that injector failure is pretty normal, and not cheap in the least bit. I have read that a lot of people use fuel addatives, but not too many people installing another fuel filter system. Do the fuel filter systems such as airdogs help out with the injectors? If so which system would be the best for injector life? To me it seems that the cleaner the fuel you put through the injectors, the longer they would run. Any suggestions would be appreciated.

Clean fuel is obviously important. However, the reason additives are used is to increase lubricity. ULSD does not have the same lubricity as regular diesel or LS diesel.

Another thing to keep in mind is that the LB7 had a higher injector rate failure than the LLY.