I spent over 40 years working in the Refining Industry both on the fuels side for a time and then the lubes division. What I learned is that a whole lot of things have to conspire against you in order for an end user to suffer phase separation, or other forms of fuel contamination. Storage site, ambient temperature, volume passed through your system, operating environment, and the quality of fuel when it entered the tank in the first place all can contribute. Refiners have made some advances in the past decade to both lower their cost to manufacture, while at the same time improving consistent quality delivered to the consumer. One major change was distribution and storage of generic un-additized base gasoline’s to their remote terminal locations. Raw gasoline has a much better shelf life then does finished product gasoline. Also, as the single terminals can now supply and distribute various brands, many small branded terminals went away and larger multi-brand facilities which move huge volumes have become the norm. The way this becomes possible is that the branded, propitiatory additives are injected into the raw gasoline approximately 4′ before it enters the delivery truck. If you visit any of the Majors and look behind their tank dikes, you will see small 1,000 gallon additive concentrate tanks labeled Shell, Sunoco, Phillips, and even “Generic” for the off-brands. A relatively short time ago the fuels were blended at the refinery and sat in huge tanks, sometimes for months before reaching the pipeline network, then out to the regional terminals. Stale gas is a rare thing now.
All this said, if you as a consumer uses nothing in the way of additives then you will likely have no issues. If you have a carbed engine and you have a problem, then recovery is a pain but doable by the average do-it-yourself type of owner. With an MPI, recovery can be a nightmare as many here have found and I feel that it is cheap insurance as a quality additive can help maintain the high pressure/high volume fuel pumps, pressure regulator, and injectors through the season extending their life and a super dose before layup along with some 2 cycle oil that coats the internals preventing rust accumulation on exposed bare metal internal components is just common sense. In these examples, what you can’t see can hurt you. For me based on my experience with internal engine maintenance and repair which is extensive, there is a notable difference between the users and the “it’s waste of money” crowd. I do not waste money on maintenance by throwing parts at my ride or a friends problem, and based on everything I’ve touched with my own hands and seen with my own eyes, I’ll be staying with Mobil-1 15w-50 and Marine Sta-bil. W