It's a big life decision - I don't know that guts is what is necessary, jobs play a big role in our society (identity, purpose, socialization, etc...)
It has to feel right emotionally and look right intellectually. Both.
If you have the numbers, then maybe spend an equal amount of time looking at the emotional side - no need to force it if it doesn't feel right, as there are no prizes for retiring earlier than some arbitrary date.