Any Regrets For Starting Extended Travel Early?

to all of you who was able to retire early how did you know that you had enough to do so. did a financial person say your good to go, or did you just figure it out on your own. I am 50 years old just finished 31 years on the job, I like to think I put my time in, I would like to start the full time adventure sooner than later but can not convince myself I have enough. seems everything I read they say you need a million dollars invested, I do not believe so, am I wrong ?