This is a bit elementary, but a good start in testing how good your balance is.
How good your swing, rhythm and alignment are…pale in comparison to the importance of good balance.
A good swing, good rhythm and proper alignment are very individual things, but balance is not.
There is a very simple test that a friend or just someone hitting balls next to you on the range can do.
Balance is all about keeping your feet under you in the setup, back swing, down swing and finish.
Obviously if you start out of balance, you will remain so, but the bad part is the direction where your imbalance points changes several times during the swing causing all sorts issues.
If your upper body moves too much from side to side, toward or away from the ball during your swing, your feet are not under you anymore and you are out of balance.
It doesn’t mean you have to be flat footed, nor does it mean you can’t have a lateral move.
What it means is your weight, center of gravity, whatever you want to call it needs to be over your feet the whole swing or you will be off balance.
Though I am not a huge fan of stack and tilt, this is one of the big positives. It’s goal is to keep you centered.
It’s hard to describe what that means in print, but here is a test.
Take a setup(position 1), take a back swing and stop(2), then make a finish and stop(3)…hard to do this test during the downswing, unless you find someone who is not too bright and needs a 5 iron to the noggin.
Have a friend stand see how much force it takes to push you off balance in all three of these swing positions from all four points of the compass.
That will tell you where your weak balance points are and just use common sense to fix it.
Example 1-if at the setup you have too much weight on your toes, if someone just nudges you on the back, you will fall on your face.
Example 2-if you stop at the top of the back swing and your upper body has made too big of a lateral move…your right shoulder is too far outside of your right foot and you can be easily knocked over so your right ear hits the dirt.
…and so on.