"I have devoted my career to understanding exactly how practice works to create new and expanded capabilities, with a particular focus on those people who have used practice to become among the best in the world at what they do. And after several decades of studying these best of the best—these “expert performers,” to use the technical term—I have found that no matter what field you study, music or sports or chess or something else, the most effective types of practice all follow the same set of general principles.
[people] assume that someone who has been driving for 20 years must be a better driver than someone who has been driving for five, that a doctor who has been practicing medicine for 20 years must be a better doctor than one who has been practicing for five, that a teacher who has been teaching for 20 years must be better than one who has been teaching for five.
But no. Research has shown that, generally speaking, once a person reaches that level of “acceptable” performance and automaticity, the additional years of “practice” don’t lead to improvement. If anything, the doctor or the teacher or the driver who’s been at it for 20 years is likely to be a bit worse than the one who’s been doing it for only five, and the reason is that these automated abilities gradually deteriorate in the absence of deliberate efforts to improve."