[mikets]

It also depends on what kind of wheels you have. If you are using mecanum wheels, you need all 4 encoders to figure out x and y displacements. If your robot can only go forward and backward but not sideways, then 2 are probably just fine. Our robot is 4-wheel swerve drive each with an independent motor and encoder. So our code can keep track of both x and y displacements.