Our threshold for enough is between $1 and $2 million.
As mentioned, it depends on one's needs. With economy changes, tax changes and market changes it can be difficult to estimate and determine one's earnings/gains to compare to one's actual needs. Having at least a long-term and short-term bucket really helps to level these up and downs.
A greater threshold (starting amount) could or may be nice, but I have noticed various folks have concerns for leaving monies after death. If it is not all beneficiary assigned/designated, your State will love you for the monies left to them.
Good luck in your endeavors.
Without social security, probably about $3M would be enough for us to maintain our lifestyle (e.g., including international travel about twice a year). With social security (plan to claim next year), it is probably under $2M.
We could easily survive on less - spending on current "essentials" only: maybe much less than $1M plus social security.
Really an individual issue. The answer for each person depends on so many factors. All I can offer is our plan. Applying the '4%' rule, we're good at $3.2M, excluding real estate, but could do fine as low as $2M invested. Thus far, 14 years into retirement, we are drawing a net of less than 2% of portfolio, largely due to a lot of dividends and capital gains. But I don't think you should just 'quit' and totally retire when you give up that day-job; you have to stay in the game and keep trying to grow, albeit with diminishing risk as you age.
My idea has always been that at any time there might be a disaster that could cut the value of investments by 50%, so I feel I need at least 2X what the withdrawal models suggest. So, taking less than the 4% rule seems like additional insurance against that black swan. As an old stock broker told me 40 years ago, more is always better.
Now that Speaker McConnell is talking about cuttings social security and Medicare enough might not be enough.
Just maybe instead of cutting we should look into stopping back door entrances into Roth IRA's or better yet cutting some of the loopholes that allow real-estate moguls to pay no taxes. I forgot we voted for a real estate mogul SORRY!