Regalvanizing is very economical, and you can do it as many times as you want.  The problem is finding a galvanizer when you want one, that will work with chain.  There is one in Jacksonville FL, but they don't have a "chain tumbler".  They galvanized my chain and it came back with many of the links glued together by excess zinc.  They warned me about this and it was fine with me, it only took a few hours with a hammer to knock them apart.  However one of the other folks whose chain was in the group (they give a discount for quantity) was sorely pissed, even though I had passed on the warning.  The tumbler would have taken my chain and tumbled it in a drum to knock the links apart.

The one proviso is I have heard that if you have 70ksi chain, the heat in the galvanizing process will cause it to lose some strength.  I'm sure someone else will chime in to explain that.

Duane
Wanderer, SM#477