About three years after I married, the Oneida Company discontinued my crystal pattern. It was King Edward -- one of the oldest patterns in their catalog, and one that had been around since the thirties. I was upset.
I'd say one thing to consider is to think about whether the pattern is apt to be discontinued, and if it happens, whether a current pattern would mix and match nicely with your original pattern.
Sometimes, your best bet is just to go with plain, open stock crystal that can be replaced easily and inexpensively, and that won't be discontinued at some point.