I don't grow mint here. It's a weed. Crap takes over.
I dry some, but generally, I eat and preserve seasonally, when the 'maters are in, so is the basil, oregano, and cilantro, then it's time to make and can red sauce italian, and salsa.
Thyme and rosemary are generally available fresh, or dried on the branch year round.
Can't grow black peppercorns, cloves, or cinnamon, though. Those have been valuable for centuries because of their restricted ranges.
/johnny
Spices can be kept in the freezer and it greatly preserves their potency. I put them in canning jars so they’re hermetically sealed.
I know that in a SHTF scenario, that freezing them is not going to be a priority, but then if you just keep the jars sealed, you’ll be starting out with them as fresh as possible.