Extreme longevity runs in both sides of my family. I could probably be one of those guys taking call into his 60s working 3 or 4 days a week well into his 70s.
But I won't. I've planned, saved, invested and not gotten greedy. If I'm working after 62, something has gone horribly wrong. Or I'm working another year to fund a completely ridiculous retirement reward for myself, like a Ferrari.
They're not cut from a different cloth, they're gluttons for punishment and probably need other interests outside of medicine.
One guy I worked with kept saying, "one more year" and "maybe next year". He had even bought his retirement home already where he spent a few weeks a year. I'm sure you know how the story ends.
Nobody says they wish they had worked more on their death bed. Work until you're in the position that you want to be in for retirement, have a back up plan, and pull the ripcord.
And, maybe I didn't win the genetic lottery after all and it skips a generation. I'm not going to wait and find out.