Hi Vern, think it depends on what kind of seeds they are , usually keep about a year or two at cool temps but I'm keeping mine in refrigerator all the time, imagine they are good there for few years, in the freezer indefinitely, again, some shouldn't be frozen, best to ask and do search.
Mine don't last longer than a year anyway, enjoy sharing.

just my opinion,
Bea

There's a forum here called Seed Saving that you might find helpful

Here is a link that might be useful: Seed Saving