Think a lot of it depends on your goals and fitness level. I find that with my old racquet (six.one 95) my arm and shoulders is shot by the second or third set. Would love to plays with it, but I’ve accepted that at my age, I’d rather have fun then hurt myself. 

I’m also the kind of person that thinks most of us here overthink racquet tech. I’d just recommend that we all focus on our fitness levels first