[smokestack]

I doubt that a lawyer, doctor, or (especially) investor could survive more than a year without constantly investing time in learning about their field.

[GFK_of_xmaspast]

Doctors now have to do 'continuing education' and many of them got pretty upset about that and / or were grandfathered out of the requirements.

[wobbleblob]

Yeah, but what you've learned doesn't effectively rot away at the same rate. Old diseases don't go away, people don't develop new organs as they discard old ones.