Hey & welcome to GT! Working through the fundamentals as a review is a great idea.

Originally Posted by: cnthetford

The question I have, is whether or not there is some disadvantage to the way I've learned it what would make it worthwhile to unlearn and learn the different way?

It depends on the musical context.

When we first start to play we try to fret notes & make chords sound in any way we can! After that we learn a few chords & try to string them together to play music. Eventually you discover that knowing more than one fingering is useful.

For example, the A major chord as you described could make it easier to get to a D major chord next. But an A major with all 3 fingers in a row (index, middle, ring) will make it easier to add the sus 4.

|-----------------------|

|---2--3---------------|

|---2--2---------------|

|---2--2---------------|

|-----------------------|

|-----------------------|

And using just your index finger to barre across all three notes on the 2nd fret will make it easier to do something like this.

|-----------------------|

|---2-----2------2-----|

|---2-----2------2-----|

|---2-----2------2-----|

|-----------------------|

|------3------3--------|

Or this A to D major!

|-----------------------|

|---2--3---------------|

|---2--2---------------|

|---2--4---------------|

|-----------------------|

|-----------------------|

The bottom line is that depending on which chords or notes you need to get from & to next (which is the mucial context), you might need to use one fingering instead of the other!

In the end, the best fingering to use for any given chord or music is the one that helps & does not hinder smooth, natural & efficient motion.

With all that mind, I encourage students to learn a variety of fingerings, because they are going to be useful depending on the musical context.

Hope that helps!