The decision to retire early is not binding. You can always change your mind later, so I wouldn't look for 99% certainty of "success." The bigger question is

The decision to retire early is not binding. You can always change your mind later, so I wouldn't look for 99% certainty of "success." The bigger question is whether you'll be happy with a life of leisure. I say count your blessings and try it out and see if you're happy without work! If so, then you can surely tweak your spending rate to match your quite significant savings.