how many years do your seeds last

do you save seeds year to year? just wondering how long your garden seeds last and how do you store them year to year. I store my extra seeds in metal resealable containers mostly from cookies, crackers and whatever containers I can acquire. this week im planting seeds in the garden some are 8 to 10 years olds some from 2019 and some I saved from squash and cucumbers last year. im not sure if they will all grow but I will try them anyway

There are a bunch of factors:
1. Do you need *really* reliable germination - fresher seeds are better then.
2. Can you keep them in a fairly consistent temperature. Seeds that I keep in a container in a fridge are more reliable longer.
3. The specific plant - carrot seeds don't keep as long as others from what I've been told. I've been told that some seeds shouldn't dry out or they won't germinate. There were some seeds from an archeological dig that scientists managed to get to germinate (but they jumped through a lot of hoops and only ended up with 1 plant, so they have more work to do!)

I absolutely save seeds and I do my best to treat them well. My public library just started a seed sharing program and they were asking that donated seeds not be more than 3 years old. However, I have a friend who gave me seeds that were younger than that, but had been exposed to high heat, and I had no luck at all with them.

If you have lots of extra seeds, people are known to do a germination test with paper towel in a baggy to see if germination happens before they try to get them to grow in their garden. That said, if they do germinate in the bag, there's no reason not to put the results in soil like you would many other transplants!