That was the key when I took lessons long ago and had to stop with that particular guy. In the lesson, he had me change this or that which I was able to do really well off the bat, but I did 3 swings and done. I couldn’t develop the feel of that change on 3 balls, so it never really stuck even with practice.
When using a swing aid, some help with eyeing a certain path while other aids help develop feel. Every student has their preferred method, whether its eye balling it or feeling it, etc.