Answer: Tomatoes, eggplant, pepper, hot pepper are relativley long lived seeds, beans and beets moderately so, and lettuce just one year reliably. You might find the seed storage chart at the following site interesting:
Seeds remain viable for differing lengths of time depending on how they are stored as well as differing for different plants. The viability also decreases over time until it reaches a point where you definitely need to replace them. For those reasons, it is always a good idea to test the germination of held-over seed to see how yours have lasted. To do this, fold some seeds in a damp paper towel and wrap that in plastic to keep it moist. Set in a warm spot out of direct sun and check for germination. This will give you an idea of the percentage you could expect.
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