When my daughter moved to the East Coast in spring 2021, I inherited a tin containing numerous old seed packets which mainly represented her enthusiastic optimism followed by dashed hopes.
The first crop that I risked were seeds from a packet of 'Endeavor' beans packed for the year 2014. The seeds looked fine – not dry and withered at all and since my own choice of fresh seed that I had planted earlier in the year had steadfastly refused to germinate I really had nothing to lose. I raked over the row from which I had just harvested potatoes and on July 19 planted the beans fairly close together. In just a few days they had all burst through the soil looking healthy and vigorous, and they went on to provide me with the best crop of tender beans ever.
Emboldened by this success, I decided this year to plant some seeds from the oldest packet of the collection which proved to be a few seeds of the everlasting flower, statice (Limoniun sinuatum). I have never grown these before and since the packet stated that one should sow them before the end of 2006 I knew that I was really pushing my luck!
There were just five statice seeds in the packet which I planted in a cell pack in spring. Once again they all germinated. I potted them on, and luckily I kept them inside until after our last frost. Once planted out they sat rather forlorn-looking for several weeks but then the rosettes of basal leaves suddenly grew rapidly and the next thing was that flower spikes shot up giving a lovely display of pink and blue. It is the calyx of the flowers that give the pink, blue or violet color while the corolla is white, or sometimes yellow. Apparently these flowers keep their color very well if dried although I shall have a hard time cutting them to see if this is true!
I also planted some seeds of Gallardia 'Arizona Sun' (2009 seed). They have grown and even produced a couple of flowers, although the plants are still small.
My only failure were old Echinacea seeds, none of which germinated.
For reliable yields, especially of food crops, one should always plant fresh seed that has been packed for the current growing year. Some plants simply will not germinate at all if the seeds are not fresh, e.g. parsnips. With our hot climate during the summer, and heated houses in the winter it is often impossible to find a consistently cool temperature in which to store seeds in order to maintain viability.
Sometimes it is just fun to experiment!