I keep self-grown seeds in paper envelopes, labeled. They need air and a certain amount of moisture needs to evaporate for them to become/remain viable. I try and store these envelopes in a cool, DRY environment. I'm basically curing seeds, without the sweating. This is how I've done it for 40-some years and it's super rare for me to find a non-viable seed, which I do by floating mine in water. Viable seeds sink after 6-24 hours. Of course, all sinkers go straight into dry-ish small planters at 1/2", which aren't watered until I see movement, then slowly so I don't flood the seeds out of place.
Some gardeners freeze hard to germinate seeds once, then plant them. (after a day at room temp?)
I've also stored in plastic vials, always slapping a little piece of tissue in the bottom to absorb any excess moisture.