It will never cease to amaze me how folks will jump over a dollar to save a dime, then try to polish the brass on the Titanic. During last year's 5+ dollar a gallon fuel, several of my customers decided to buy non top tier fuel to save maybe 50 cents per gallon on fill ups. This, in spite of me constantly cluing them in to the dire necessity of using top tier fuel.
Sure enough, 3 of them cam in with check engine lights on, and ash on the spark plugs and on the oxygen sensors, sporting numerous DTC's. These 3 had to have new plugs, all the oxygen sensors, and new catalytic converters.
The total tally on them was a lot. The savings was nil. In the big picture of life, there are few shortcuts which work effectively. The piper must be paid, so to speak.
The same goes for top tier oil.