If you use FP Plus or FP60 on every tank, you will never need to use another fuel system cleaner. This is why I use it. My '97 Camry V-6 had FP Plus in the tank for over 100,000 miles with no other cleaning of the fuel injectors. The inside of the engine and injectors were squeaky clean at 200K when the head was removed to adjust the valves.
You still need to occasionally clean the throttle body (air) side.
For the engine cleanliness, I ran Auto-Rx then Red Line oil. I would use one Auto-Rx cycle for the engine cleaning.
In the last few years, some people on this site have become increasingly hostile to FP and Auto-Rx. I don't know why. They are top notch products.