To me, the only reason to swap centers is for appearance sake. Some prefer the scalloped centers with loop rims and hat centers with hat rims. If the "look" doesn't bother you, no need to change.
When I got to that point, I just paid Tucker Tire to send me new tires with new tubes mounted on new loop rims. They arrived a week later and the whole deal cost me $700, including shipping. THat was in about 2005 and the cost has probably gone up, but it was cheaper than I could find having a local shop do the work. I later filled them with RV antifreeze.