Baking soda has a long shelf-life.1 Steer clear of those small cardboard boxes in which baking soda is often packaged. Instead choose baking soda in #10 cans or repack it into a PETE container for ideal storage life. A typical #10 can contains 576 teaspoons.3 I also store baking powder and yeast as a part of my longer-term storage. All store well in cool, dry conditions.2
1 - LDS Church News
2 - USU Extension
3 - Emergency Essentials
All of these oil-based products have very short shelf lives – anywhere from 6 months to 2 years. When they get too old, they are usually inedible. Because of this you HAVE to rotate these products regularly. One way that you can keep these products regularly rotated is to donate any items that are close to date expiration (but not over) to a local food kitchen. Extra Virgin Olive Oil is supposed to store longer than other oils, but is also the most expensive. By storing and using a variety of oil products (see above), you are more likely to be able to rotate within appropriate time frames.
The thing that I've noticed about using older oil from my storage is that it tastes/smells just fine when I first open the container. But if the oil is very old, it becomes rancid very quickly. Because of this, I like to store my oil in very small containers. It makes it more likely that I'll be able to completely use (and not waste) a container of oil before it goes bad. It also helps to keep oil products in a completely dark area. I double pack my oil bottles into boxes so that light exposure is limited.
1 - World War II Food Rationing
Salt is a good preservative, but I would say that taste is the most important reason to store salt. Have you ever had cookies/oatmeal/fill-in-the-blank without salt? It's terrible! Salt, like sugar, makes most things taste better.