Some years back, I had the good fortune to speak with Bob Brett when he was coaching Goran Ivanisevic. Bob has always been an advocate of taking time away from tennis. He realizes that no player can sustain excellence at all times. In his mind, the only way to really succeed in professional tennis is to take breaks throughout the year. This is not to suggest that the player should avoid remaining in condition.
Most modern coaches promote the concept of periodization.
Periodization is a planned approach to competition that is based upon balance. Their training regimen is designed to allow for peak performance at these predetermined times. Combining off court training, cross training and increasingly challenging competition, periodization is, in my mind, the most balanced approach to training. The summer may be the time of year when you can play tennis most frequently. You probably are competing but reasonably.