To be generous, if we're talking coding specifically, 4-5 years is a reasonable cap in my opinion. Coding is not the same thing as software engineering or syst

To be generous, if we're talking coding specifically, 4-5 years is a reasonable cap in my opinion. Coding is not the same thing as software engineering or systems/architecture design or technical leadership or... All of those things can be improved significantly through a human lifespan. The act of writing code? Not so much. The other caveat is that most people will not be getting enough experience to hit that cap in 5 years. You need the right environment, mentors, etc.