Road force AKA on the car balancing is worth it's weight in gold if the car can't maintain balance and the tires are not defective.
My 87 300E was extremely sensitive to balance. I had free lifetime rotation and balance at tire America. Every time I rotated and balanced I always a vibration that took multiple attempts to correct and it was never correct. I would go to a different Tire Am and get it re done and they would say "your tires are waaaay out of balance", I replied "I just had them balanced in Dublin yesterday", reply "maybe you threw a weight"- NOT.
I went to test drive an Alfa Milano Verde and learned from the owner about "on the car balancing". Took the MB to E.T. Paul downtown Clumbus and got it done. The car was perfect, the tire, wheel, rotor, bearing, and any other moving part was balanced. I NEVER balanced or rotated from 120K to 155K when I sold it. Many cars are not this sensitive, you can throw a set of tires on an old Impala and it doesn't matter, always smooth.
I bought a tire depth guage from Napa for $5.00, this should determine when if ever to rotate, not some arbitrary lemming like "every 5,000 miles." My dad has 35K on his Town and Country and has never rotated and has even wear on a FWD-the proof is in the pudding, not in the recipe.