The only changing of grips that I have done, is to change the grips on my fly rods to match my hand grip diameter and shape.

I don't understand why most commercially made fly rods all have a 3/4 inch diameter grip, and only offer the grip is one style.

I have been told that the reason is tradition.

I question that they have been doing it all wrong for over 500 years, and will not consider that they have been doing it wrong, because of tradition.