Seeds have a shelf life (as all living things do), and depending on where your particular shelf is, the viability of your seeds can vary by as much as a year or two.
When someone asks, “How long do broccoli seeds last?” a safe answer is three years, but in ideal conditions your seeds could still actually sprout after five. So, you see where our dilemma lies.
Our seeds would live in this cool, dark, dry environment and 10 years later, those very first tomato seeds we’d ever bought would still be viable.
In reality, our homes go from hot to cold at the turn of the seasons, we sometimes forget our seed packets outside overnight (or at least I do), and an old shoebox will have to do for storage.
Every time a seed experiences less than ideal conditions, it suffers a decline in quality. It may not die right away, but it might take a little longer to germinate.