I was just reading through these swaps trying to get an idea of how they worked and if I'd like to do it just for fun (don't really want/need any seeds with the exception of heirloom vegetables). I noticed under the topic "Questions", that it was said to consider even older seeds. I agree with this, while there are those few that are actually only viable (good) for one year. And I know of several that are good for only 2 years, including columbine (aquilegia) and delphinium (which are not listed on the following link). Here was a quick list of some common flowers, vegetables and herbs.
http://www.clearcreekseeds.com...
