I guess the east coast is saltier than the west, that might explain a few things over the years...

Jake is right that any lube doesn't do much good in a leaf spring. I can also tell you that my leaf springs on my Trailex, which I replaced a few years ago, started rusting a few months after I installed them, and I coated them with WD-40 and didn't move the trailer, and they were never in saltwater or any water other than rain. Clearly I didn't get the galvanized variety (I think I ordered direct from Trailex), anyway, oh well.