Overcoming USLD is really incredibly simple, just add a fuel additive.

Power Service
Power Service
Optilube XPD
Diesel Fuel Improver

There are a lot of guys with original injectors well into the 150k+ miles on 6.0Ls, some of them have never used a fuel supplement in the life of the truck, some have.

Injector problems from USLD are really the least of your worries with Ford diesels.... there are plenty of other problems to go around depending on the model years you're looking at

The new 6.7Ls are having issues with the Bosch high-pressure fuel pump grenading the fuel side of the truck, but despite what you read here the problems are not nearly as prevalent as issues with earlier diesels were.