Male high 3.5 player, used to play A/Opens 30+ years ago. I"m old.
"Play". That is the operative word.
Pick up doubles with friends, any decent ball.
Practice sessions, mostly hitting, any decent ball.
"IT COUNTS" matches, only new balls.
Practice matches, any decent balls.
Most weak hitters bring dead balls.
Lots of big hitters bring really lively Wilson balls.
Average hitter like me brings new DunlopHDHardCourts, the heaviest and hardest balls.