Probably the best way to keep your cats and engine clean is to run good quality fuel and drive the vehicle normally with an occasional WOT blast every now and then.
Generally your cats are meant to run around 1600 degrees max during and after prolonged hard usage, and it is at this temp pretty much everything that shouldn't be in the cat will burn off.
If there were rampant cat failures or issues Ford would most likely be in hot water for emissions compliance, and the average vehicle owner doesn't even know what a cat even is, so generally it has to be one of the most robust and reliable parts on a stock vehicle.
If you have a tune or tuner that neglects the maximum temperature a cat can sustain, that will seriously degrade the life of a cat along with unnecessary enrichment at WOT or a 2 step.
In short, run good 93 every now and then, perform proper routine maintenance, floor the truck occasionally to get some heat in the cats, and send it.