Anyone use fuel system cleaners?

Fuel additives.
Me.... ~3oz. every 10 gallons in modern everyday driver car. Tecron once or twice a year.

Carb cars ... Put some Lucas down the carb vent tube if it's not going to be run for some time.

In my 3500 Cummins I add 8ox of 2 stroke oil every fill up. That's approx. 500:1 ratio.