When FI bought my e-ring, it came with one free rhodium plating from the jeweler. I've had my ring almost a year (one year on Sunday) and it really didn't need to be replated yet. However, since it wasn't from a chain jewelry store and I'm moving away next week I figured I would take advantage of the free plating before I left. It does take a few days so keep that in mind, but it came back just as gorgeous as the day I got it. I've had it shined up a few times over the last year, but the new plating truly did make a difference even though there wasn't that much wear and tear on my ring yet.
I believe to get it done in the future (from that jeweler anyway) will cost about $25 each time. I imagine that would be similar with most jewelers. I think I will definitely get it plated right before the wedding again so it really shines in the photographs and looks its absolute best.
I know many of us have white gold e-rings, so I figured this might be some good advice. I may even redo the plating every year or so just to take extra good care of my ring in the future. I definitely think everyone with white gold rings should consider this. If you don't want to get it replated, at least remember to get it cleaned and shined up for the big day