Answer: Seed viability depends on a number of variables including the type of plant (tomato seeds for instance generally last a number of years but sweet corn seed lasts but one or two) and on the storage conditions under which they are kept. Temperature and humidity have a strong influence on seeds, as do original harvest quality and subsequent handling of the seeds. Even under the best of conditions, germination rates will naturally decline over time. This is why many gardeners prefer to purchase freshly packaged seed each year, and why seed is labeled with a packaging date rather than an expiration date.
With regard to hybrid vs. non-hybrid seed, this depends on the specific plants/varieties you have in mind as Burpee offers a broad selection.
Q&A Library Searching Tips