Depends on your age, height, body type, physical strength, athletic ability, injuries etc...
Example: 40+ yr old with bad tendons do not need to be emulating Fed/Novak/Nadal etc..
. These guys need to just bunt the ball back deep like Mac & Connors did.
50% of the guys in my age group who try to emulate Fed, Nadal etc end up with chronic wrist, elbow, and shoulder problems. The rest of the oldies who still play like they are in the 1980s are just fine.
For juniors and other young players too, your height and body type does matter..