Robin
I dont think there is any definitive answer to this one. I think it is generally good practice to try to get the most recent ones you can - the year of manufacture will be stamped in a circle as two numbers ie 85 or 98, meaning 1985 or 1998. I have had very poor condition roadwheels, lots of cuts, stones etc, which have lasted very well, and also very new looking wheels still with the mould marks on which have kind of rolled off the rim.
I have heard that they dont like being stored for long periods, this is why i got rid of some of my spares a while back. Having said that, i might get a few more now that there are a few around.
Chris is still working on the project to get roadwheels remanufactured but i guess there isnt much call for it at this stage - i have started hanging on to my old ones though, just in case!!!!
Cheers
Tim