Man oh man. This discussion has a history. Rearing its head in a slightly different form. First of all it may help to do a search on the forum under this subject matter. There have been extensive discussions on this issue. From that you can make up your own mind. You will certainly have numerous well thought out opinions of great diversity from which to choose.
To put it succinctly in my opinion, I would say that shelf life is not so much a matter of time, as it is a matter of exposure. I've seen hermetically sealed rods weld beautifully after years of sittin on a shelf.