normal fuel additives
I believe that most fuels available at the pump contain some additives to help keep the fuel system clean. However, over time I suspect that the fuel injectors eventually accumulate a build up that affects the spray pattern and the fuel flow. That is why I periodically add fuel injector cleaner to my fuel tank. My first fuel injected vehicle was a Volve and at the time the only brand of cleaner endorsed by Volvo was Techron. I have recently read in one of my engine rebuilding books that some harsh fuel injection cleaners result in deposits being formed on the valves. After more than 30 years, Techron is still the only fuel injector cleaner I have ever used.