Gardening

Right now, I'm buying commercial seeds for all my stuff. Not a big deal right now. I can't even grow this much all at once on my balcony, and the seed bags for 2 bucks each last years sometimes :)

From what I know, sticking to seeds made by breeders makes total sense for high value crops like cannabis, peppers, tomatoes, etc., because otherwise the quality will suffer, for example due to uncontrollable cross pollination.

But for many other things, this shouldn't make much difference. I'm thinking of herbs or lettuce as example.

One thing I also heard is that modern varieties don't even produce viable offspring. Therefore, getting "legacy" varieties are the only option, but with worse harvests because they haven't been selectively bred for decades.

Seeds cost money after all, and in the future, I want to be as independent as possible when I have a big garden or some sort of.

What stuff can I let go to flowering and save the seeds for next year, and where does it make sense to continue buying them?

And what did I get wrong? Is this BigSeed™ propaganda?

Also, under which conditions should I store them to keep them viable for as long as possible? Fridge? Room temperature? Vials? Paper bags?