I'm not sure exactly for what you are looking. The graphic in the lower right hand corner of the screen (Called "HITS" - under the ball) tells you how much life if left in your ball. If it is RED and just a little less that 50% remains, you can probably get 18 holes out of it - but if the match is really important - buy more or change! Please understand that I am not "talking down" to you - just unsure as to what you want.
If you open a "practice round", you can see how much life is left & immediately closing the screen after a peek doesn't affect anything.