Every time you walk on the court things will be different.
Even the best players have to be aware of how things are going and how they feel on that day. Of course, the ideal adjustment would be to hit the shots that you are having trouble with a little better. However, sometimes it makes more sense to use what you have on that given day.
There will be times when adjustments should be made depending on each individual player’s ability to execute specific shots. Also, it is important to realize your opponent’s strengths and weaknesses and play the shot accordingly.
Finally, there are other variables that may occur in a competitive situation such as the weather conditions, speed of the court, and the footing (slippery or sticky court surface) which can affect your ability to do what you would like to do.
Try to pay attention to some of these things as the match progresses and make some small adjustments that you believe will give you a better chance of a positive outcome.