There is no requirement to use any of them. Using a winter formula when it is cold is a great use case. Other times of the year not so much. More of a personal choice thing. Find a quality fuel that works for you both in economy and good running and stick with that. QT here has rather good fuel. Lots and lots of posts already here to read on this subject. I have tried some of the name brands with no real results, outside of cold weather formulas.