The way I look at it is... yesterday I filled up 12.789 gallons at the price of $3.129 for premium, to a total of $40.02. Now lets say I had filled up the same amount at the price of $2.852 for regular, to a total of $36.47. Looking at it from this perspective the difference in price is so marginal that I definitely choose to purchase higher octane gasoline. I am a college student and thrifty when I can be, but this is just an example of weighing the pros and cons. Pay $4 and get better mpg, smoother performance (in my opinion), and peace of mind your engine has what it needs.