It would help to know what all chemicals you are talking about. They all have different stabilities and shelf lives.
In general, chemicals should be stored dry and sealed, out of the light. Some are best in the fridge or freezer.
K-meta is very stable and should be fine stored at room temperature even for years. I've used K-meta before that was probably 20 years old with no problems.
Tannins, rock solid. Yeast nutrients and DAP stored dry and out of the light will also last years.
K-Sorbate is more sensitive. The general consensus is that it has a 6 month shelf life. But to be honest, if it is stored in the dark as a dry solid and not heated, it should last much longer than that. But it is useful to refresh it before it gets too old. I store mine sealed in the freezer. I expect it to be good for about two years. Solutions of sorbate will decompose much faster.
Yeast are good even past the expiration dates on the packages. I also store yeast in the freezer or refrigerator. I've used some yeast successfully up to two years past the expiration date when stored in the fridge. But yeast is relatively cheap and it's best to use it fresh if you have any doubts. It's not like all the yeasts die on that date. It slowly loses viability and there may be less viable yeast populations until you get to a point where there just aren't enough to get things going.
ML Bacteria are more sensitive. They can be stored in the freezer (dried) for 6 months. Some should still be viable past that if still sealed and dry.
Enzymes are also more sensitive and should be stored in the fridge. Depending on the enzyme, they can last a year or so.
In general, anything that is a dry solid or powder will last longer under the appropriate storage conditions than things in solution.