It depends on the model how it's rudder helps or hurts the turn. So the advice you've gotten is like most advice you will get over time. Sometimes it suits, sometimes it doesn't. Most times, the advice will be way too short and simple.

One bit of advice about using the rudder. Learn to use it early on and you'll wind up being a lot better flyer. It's the best and safest way to correct heading on final approach.

When used in normal flight in a turn, or to correct on final, very little is needed.

Lots of modelers scoff at ever needing to use rudder. Their flying usually shows how useful it would be.