What are other common / frequent things that people stock up on, that will last a long time (months to a year?)
It sounds like many here don't provision like that. If you are interested to learn more of the tricks of the "trade," you can get a lot of information from sailboat cruising boards. Or at least you used to be able to.
As someone mentioned above, the first thing is that many foods that we "know" need refrigeration don't. Some don't need it at all, and some only need cool storage (say 50-55º).
A classic read on the topic is "Care and Feeding of the Sailing Crew," by Lin Pardey. It's also a fun read if you like that sort of thing. What she does is chronicle their voyage from Japan to the PNW, something like 45 days out. She goes over the provisioning, and then the rest of the book is sort of like "one post a day" about what they are eating, how she's managing the stores, plus sailing news and a few digressions.
When I sailed we didn't have refrigeration, and most of the time we were in the tropics. Here are some of the things we did (we were not "pros" like the Pardeys).
- Bought unrefrigerated and unwashed eggs (call a farm) and then put them all together in those dozen containers they make for camping. Turn container once a week.
- Brought lots of ingredients for baking bread, cookies, cakes, quick breads. With these ingredients (flour, sugar, yeast, flax seed, baking powder, cracked wheat, raisins, etc.) you can make fresh food from basically powder! Nothing like the smell of fresh bread wafting up the companionway as you cruise along (butter will keep in those cool areas or there is canned butter for really hot places).
- Stocked up on "treat" items in cans or jars. These are things that really zing up a meal, yet keep forever and don't take up a lot of space. Examples would be black olive tapenade (spread), roasted red peppers, capers, pickled ginger (wasabi powder), olives, etc.
- Dried mushrooms, sun-dried tomatoes, etc.
- Spices galore.
- Pots of fresh herbs if you have the space and inclination.
- Good old canned fruits and vegetables. Instead of a variety, we stocked up on four or five favorites (I'm not a fan of canned foods, but there are a few I'm okay with).
- Things in long-pack cartons (coconut milk, soup).
- Canned treats such as certain types of creams.
- high quality powdered *whole* milk
- Hard cheese.
- Vegetables that keep well, and be mindful of not storing certain ones next to each other (they can cause each other to ripen sooner). Think of olden days root cellars: Potatoes, carrots, onions, cabbage.
- Fruit such as oranges, bananas.
- Condiments such as good balsamic vinegar, powdered wasabi, hot sauce, etc.
- Tea, any powdered drink mixes you actually like, instant coffee if you drink it, cocoa mix, etc.
- Stand-bys of peanut butter and jelly, if you like them (they become more wonderful on fresh, boat-baked bread).
Then of course get fresh food whenever possible and eat that instead (since the stores are mostly long-keep items, they can just wait until you need them).
We weren't big meat eaters, so my list reflects that.
This isn't food, but my motto was "It's never going to be any easier to provision (we had a car before we left, local stores were well-stocked)." So we added cases of paper towels, toilet paper, and other often used similar items. They are light, last forever, and are easily crammed into odd spaces.
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Most people here don't have the desire or need to provision this way. You may not either but since you asked, that's my take on it.