There are a few different approaches you can take. First, in an in-house test of an employee vehicle, Berryman B-12 Chemtool Fuel System Cleaner (part #0116) was safely used at double the recommended concentration for more than two years with no adverse effects whatsoever. That certainly suggests that you could run the standard concentration of 1 oz/gal for quite an extended period of time. Alternatively, you could also apply a high-quality fuel system cleaner on a more regular basis than the directions might otherwise indicate (but certainly less than with each fill-up!). Berryman B-12 Chemtool Total Fuel System Clean-Up (part #2616) and B-12 Chemtool High-MileEdge Fuel System Cleaner Concentrate (part #7516) are two such products. Using either of those products once every few thousand miles should keep your fuel system in great shape.