Different fuel detergents clean different components in different ways/degrees of cleaning. So I understand the concept of switching fuel brands occasionally to get the benefits of different detergent packages. But as long as you are keeping up with the basic maintenance required for your vehicle, this isn't something we need to worry about. I can't remember the last time someone said they got "a bad tank of gas" or experienced a driveability issue that was proven to be caused by the fuel.