For me, it depends on how long the gas will be sitting in the machine. Today's crap gas has about a one month shelf life before it starts to get gummy and clog up the tiny jets of small engines. If I know I'll be going through a tank of gas in under a month I run standard 87. If it's something like a generator, or chainsaw, that may sit for a long time with fuel, I use recreation fuel, just in case I forget to drain the fuel when I'm done using it. Also, towards the end of the mowing season, or snow blowing season, I get 5 gallons of recreation fuel, add Seafoam to it, then run that until it's time to put the equipment away. Then I know whatever fuel is left in the tank is good for several months.