Becky, daylily seeds are considered relatively short-lived but, as has been said, it depends also on how they are stored. For more info see this article on harvesting and storage of daylily seeds on the AHS site, click on the bottom of the three articles on this page:
http://www.daylilies.org/AHSar...
That said, I've heard of people getting germination from daylily seeds that were fairly old so you've not much to lose by trying. You can test viability by dropping a few of the seeds into hydrogen peroxide:water at around 1:5 to 1:9 and leaving them at room temp but out of the sun for a couple of weeks or so in the solution.
