If you bought the seeds, they have a date. If not, hopefully YOU wrote the year. Some seeds can be good for many years, but others are rather perishable.
https://joegardener.com/wp-content/uploads/2020/12/Seed-Longevity-Chart.pdf
Long story short: if you have old seeds, toss them. In your garden, in your compost pile... Anywhere where they could still surprise you and germinate:
You will be better able to organize if you let go of the unusable or nearly unusable.
I save my seeds in favor boxes that I buy from Michaels. (An art & craft store here). Favor boxes are made of thin cardboard, so don't put them where they'll get wet. Little boxes 2" X2" X3" are the perfect size for pumpkins and other cucurbits...
I've re-used boxes for years, just changing the label.
I put those boxes in a few different places. Most are not afraid of the cold. They can be placed way up in the coop, above the chickens: It will be quite cold there, but not below zero.
The insulated garage, with a small heater + thermostat can be kept just above freezing, like refrigerator temperature. To encourage me to be vigilant, I put a lot of my canned goods there, in glass jars.
The rest, I keep here, in the office.
I try (but I'm afraid I have not been always consistent) to make a census of them on a spreadsheet, along with where I stashed them.
When the snow is gone, change of plans: I bring them out by planting date:
Some are cold crops (peas, lettuce, radishes... ) will have to go in the ground first.
Melons, corn and the like, warm crops, will go in later.
Of course, there are also
cuttings of bushes, like raspberries, black currants and others. Last year, I thought ahead and made cuttings of black currants late in the fall, after the leaves had fallen. I stashed them outside, in a pail of dirt and dedicated a 2" pipe, 1 ft long to each of them. (I love that system: I cut chunks of PVC, like 1 ft long, stand them up in tall totes with a few small holes about 1" from the bottom, on the sides and fill all the pipes with good soil. This way, I can put 50 cuttings or so in one tote.
They stay outside all winter and when I see them take off in the spring, I pick up each pipe and check for roots at the bottom. when the roots start coming out of the bottom, I know they are good enough to plant.
For chestnuts, I wrap them up in a blue Scott's towel, get it wet then squeeze most of the water out of it. In March, most have started germinating and I put them in pipes just like the currants.
Chestnuts are very touchy: You don't want to mess with the root, which is very fragile, because if you break it, you'll just have to throw it: It would never make a tree.
I wish I had a hothouse or a solarium, but I do not have much room in the house: Only 3 shelves are facing East and South windows, so spots for starting stuff inside are rather limited. I buy a number of plants (herbs in particular), as most are hard to start...
I guessed I went a bit longer than just answering the question. Sorry: It's all gardening, though.
So yeah. It's messy. It's complicated, but I love it!