That’s once you have mastered the basics.10,000 hours of practice is the rule of thumb. Violin, woodworking, etc. That’s a lot of shaves.
So 10,000 hours or 20,000 shaves that each last 30 min (closer to 20 min, but this is for the sake of argument). Divde by 350 and you need 57 years of shaving.
Now subtract the years that I used carts and I might make it if I live long enough!!