Fuel storage applies in self reliant situations for such things as generator fuel, heating oil, kerosene, stored diesel and gasoline for transportation or ATVs, etc. Fuels tend to break down more easily than they used to, and lose BTU rating at the least, and even become non viable for their intended purpose over time. Ever let the lawn mower sit too long, and the tank smells like varnish? That's what happens over time, and sometimes not all that long of a time.
Fuels should be stored in cans, drums, or tanks approved for the purpose. These should be out of the sun if possible, and in a ventilated place to keep buildup of fumes from occuring. There are stabilizer chemicals designed to improve the burn and stabilize fuels for storage. There are gasoline specific and diesel specific formulas. The best, in our opinion, are the products from Power Research Inc., known as PRI-D for diesel, fuel oil, kerosene, and PRI-G for gasoline. These are industrial grade products, highly concentrated (one quart treats 500 gallons), used by industry and the military. They improve the burn of fuel, clean the fuel system, stabilize fuel against degradation, and in some circumstances, restore fuel that is going bad. This can be used for generator fuel (gas or diesel), heating oil, kerosene for a kerosene heater or kerosene lamps, and any gas or diesel used in vehicles or seasonal 'toys' like ATVs, snowmobiles, motorcycles, boats, race cars, hot rods, muscle cars, etc.
Diesel and kerosene fuels can build up water in the bottom of the storage containers in storage, and algae can grow in this water. Sounds stupid, but true. Diesel boats and RVs or busses that sit for long periods are good candidates. Power Research also makes an algicide that will treat this and kill it if you find a supply with this problem. Keeping the fuel containers full, sealed, and out of extreme temperature changing environments if possible help mitigate this problem. Fuel that has sat untreated and started to go bad can sometimes be restored, depending on the condition. The appropriate amount of PRI-D or PRI-G can be added, and then the tank must be agitated, either by a long rod stuck down in the container, or pumping from the bottom of the container back to the top. Pumping into a second container with the stabilizer already put in is also an excellent way to agitate. Vehicles with fuel systems that have been sitting, can have the fuel in the tank treated, if it's not too bad, but fuel in the lines and carb or injectors will not be treated. This should be purged into a can until treated fuel reached the engine.
Any fuel other than propane that you put up should be treated. Intending to rotate it doesn't always work, and if you need it, you need it to burn. Keeping the gas in the cans you use for a lawnmower, weedeater, motorcycle, or any other internal combustion engine should routinely be treated, so the fuel is stabilized, in case you put the item away for a while. Any fuel in a generator fuel tank should be treated, as these tend to be used infrequently. You'd be surprised at the number of emergency generators that wouldn't start or run in the last big East Coast blackout. Some were from starting batteries that weren't properly maintained or kept charged, and some were fuel system problems. Keeping the gas treated in that hot rod or muscle car that you only drag out in the good weather, is an excellent idea for obvious reasons. Same thing for the bass boat, etc.