Agree with our pal charliefed above.
Now that I'm 47, I'm doing more to stay ahead of things and I've taken on a couple of habits that have been substantially helpful for me. The first one is remembering to get a couple minutes of stretching done before I get into the car to drive home. Sounds like a very small thing, but it's been a huge help. I also stretch every night before I get into bed.
I like to ride a bicycle for exercise and I racked up some miles through the months of May and June as I got back to some better off-court maintenance of myself. The difference I enjoy in both my endurance and recovery when the tennis work/play gets busy has been phenomenal. Tennis can generally bring a whole lot of pounding to our bodies, but a little deliberate work away from the courts (nothing heroic necessary) will add up in a hurry. The bike adds zero extra pounding to my legs, but helps me a ton if I get out maybe twice a week.