How often should fuel injector cleaner be utilized to maintain optimal engine performance and efficiency? Is there a definitive timeline that should be adhered to, or does the frequency hinge upon various factors such as driving conditions, vehicle age, and usage patterns? For instance, could frequent stop-and-go city driving, or long highway commutes, necessitate differing applications of cleaner? Furthermore, can one ascertain the appropriate frequency based on symptoms such as decreased fuel economy or rough idling? Is it wise to consult the manufacturer’s recommendations, or do expert opinions suggest a more individualized approach based on the specific characteristics of one’s vehicle? Should one be cautious of overusing the cleaner, potentially leading to adverse effects on the fuel system? Ultimately, what signs should one heed to determine an ideal cleaning schedule, ensuring the engine operates at its most efficient while preserving its longevity?