I don't know what you guys are paying for gasoline.... My line of work is in petroleum for about 31 years now, so here are some tricks to get more of your money's worth for every gallon:
Here at the Kinder Morgan Pipeline where I work in San Jose , CA we deliver about 4 million gallons in a 24-hour period thru the pipeline.. One day is diesel the next day is jet fuel, and gasoline, regular and premium grades. We have 34-storage tanks here with a total capacity of 16,800,000 gallons.
✅ Only buy or fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground the more dense the gasoline, when it gets warmer gasoline expands, so buying in the afternoon or in the evening....your gallon is not exactly a gallon. In the petroleum business, the specific gravity and the temperature of the gasoline, diesel and jet fuel, ethanol and other petroleum products plays an important role.
A 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps.
✅ When you're filling up do not squeeze the trigger of the nozzle to a fast mode If you look you will see that the trigger has three (3) stages: low, middle, and high. You should be pumping on low mode, thereby minimizing the vapors that are created while you are pumping. All hoses at the pump have a vapor return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapor. Those vapors are being sucked up and back into the underground storage tank so you're getting less worth for your money.
✅ One of the most important tips is to fill up when your gas tank is HALF FULL. The reason for this is the more gas you have in your tank the less air occupying its empty space. Gasoline evaporates faster than you can imagine. Gasoline storage tanks have an internal floating roof. This roof serves as zero clearance between the gas and the atmosphere, so it minimizes the evaporation. Unlike service stations, here where I work, every truck that we load is temperature compensated so that every gallon is actually the exact amount.
✅ Another reminder, if there is a gasoline truck pumping into the storage tanks when you stop to buy gas, DO NOT fill up; most likely the gasoline is being stirred up as the gas is being delivered, and you might pick up some of the dirt that normally settles on the bottom.
These 'economy tips' only make sense at the size and scale of an oil terminal, not 'pumping gas for your car'. If a facility like his saved a small fraction of one percent on the 4 million gallons per day he mentions, it adds up to a large sum of money (which is why they do it).
But if you followed these suggestions to the letter, you'd save far less than a penny per tank.
(Source: I used to make a living analyzing cost savings for oil terminals.)
The last item, however, is legit.
One reason I disagree with your statement is because of this. If you never allow your tank to get below a half a tank of gas, you’re gonna have less problems with your fuel injection system. Allowing your car to run out of gas, or filling it after the light comes on, means you’re going to have more issues with sediment getting up into your fuel injection system. That costs a lot of money to repair. So I just smart to never allow your gas tank to get below a half tank. The savings on your overall fuel injection system is well worth doing it that way.
There is a filter, maybe two, between you gas tank fuel line and the carburetor so any sediment is not going to get to the carburetor. I remember, and it was a while ago so I could be wrong, seeing both a paper filter and a stone filter in the gas line. That was like 40 years ago so things might have changed, but certainly there is at least one filter in the line. Sediment could clog up the filter I guess, but it won't get into the carburetor or fuel injection system.
A point on the OP’s 4th point — about not pumping gas during fill of underground tanks…. There is a high grade filter on each gas pump to catch anything that could come up from the main storage tanks. I think this idea comes from decades ago when they didn’t have the filters on the pumps.