It is really best to use rudder manually before using a mix. There is nothing wrong with using mixes to make airplanes fly a little 'better', but that is personal preference, and you should understand how much rudder YOU want mixed in, and when you want it.

Using a mix is not 'free' - it might help with turns, but it will affect the airplane in other ways that you may not want. A roll, for example. You input aileron to roll the plane, but your mix is adding in rudder, so you get a barrel roll instead. Or when landing, you might want some wind corrections with aileron and elevator w/o rudder.