Browniedc:It is very difficult to use balls not knowing how much usage is left on each ball and no ability to change balls during a game.
Why do you think so?
Before entering the game, you see the type and no. of balls available in your bag. Change in the inventory or buy more in the Pro Shop without a hustle.
Starting the game or when loosing one, you are informed and asked to buy if you're on the last one. This one-click-buy button is my favourite - it can't be easier to stock up.
If that fails, you can still visit the Pro Shop - unthinkable in a real game!
The only downside is, you have no choice of a different type. These are the conditions of the game, no "it should be" to your liking.
Get used to it!