YES it is a good idea to do this. I use a switchable mix and start by mixing the elevator correction only. I have also mixed the aileron correction in the past for pattern stuff but on my 3D models don't bother with the ailerons.

3 to 5 flights usually gets it done.

BUT not doing it is also a good idea at least early on in your flying career. If you learn to compensate for all these problems by flying all 4 axis on the box, then dealing with diversions from the intended flight path become automatic reflex actions.