Be advised. I am ASE certified in suspension and brakes. Something is going out / or something is loose. I last actually aligned the dually about 4 years ago. I have touched it up from time to time, but it hasn't officially required any adjustment. I check it yearly, but I have my own alignment rack. If you actually need an alignment, something has been bent, moved, or worn out.
Someone hit a curb and not tell you?
What do mean by touch up ???
I run 2/32nds toe in for best milage. I also have gone round and round with frontend guys. The rest of the deal is usually fine, Caster/Camber. If the truck goes off-road at all I always recomend having the alignment checked and have any adjustments done every 6 - 10K. But I am also the guy that gets just shy of 100k out of BFG muds and has 478K on my truck.