I go through a lot of gas during the year using about about 3 gallons every time I mow my lawn. I keep about 60 gallons on hand and faithfully rotate it. At the very end of the season I add Stabil to it. I also fill the tank on my truck no later than when it gets down to half a tank. It having a 36 gallon tank is a plus too.
The other thing is I keep 6 of those 20# propane tanks as that’ll come in handy come SHTF plus the house has two 100# tanks for a propane stove that heats the back half of the house. That stove doesn’t need electric to run so it in combination with the wood stove for the front half of the house serves us well when we lose power. The front half of the house also has oil hot air heat with a 275 gallon tank that we rarely use, so all sorts of fuel around here.