2 sets of wheels dilemma
 

I was thinking about buying a second set of rims and putting bfg 37" 12.5 mud Terrains on them

Currently w/ stock 35 all terrains

Would it be required to have an alignment done everytime I changed the wheels? or would they work fine?

Re: 2 sets of wheels dilemma
 

Put the wheels on and go! No need to go back to the doctor.;)

Re: 2 sets of wheels dilemma
 

^exactly, if the truck is aligned properly just changed the tires really shouldn't mess with anything. If you're lifting the rig, changing suspension components, leveling kit, etc then you would need an alignment.