It mostly boils down to what the definition of the "lifetime" of a car happens to be. Most cars are given a "lifetime" by the manufacturer of about 5 years (generally because many owners will replace their car in that many years). This is why you don't see any "lifetime" replacement parts warranties or on new cars. Since the filter in the tank is a serious pain to replace, I'd have a shop check my fuel pressure. If it shows below the minimum operating pressure, you might just replace the pump and the filter. A 6 year old car shouldn't need a pump/filter unless it has gotten dirt/water in the tank. You will get some moisture due to condensation inside the tank and this might cause a few rust particles in the tank (which would get picked up by the in-tank filter).