It isn’t just how MUCH you have.
The amount of money that is enough can change depending on how the money is received.
Let me illustrate with an example:
Newspapers in the 80s and 90s used to run competitions where the prize was a choice: “Win £250,000 in cash, or £20,000 a year for life!” The cash lump sum was a lot of money, but the alternative was potentially much more depending on the circumstances of the recipient. If the winner was an 85 year old lady then chances are the lump sum would be far more attractive, whereas if the winner was a twenty-something then the annual payment could well be a better option.
Also, the market and financial circumstances appropriate at the time could well influence the choice. So, say interest rates on deposits was running at 10% per year, taking the lump sum and putting it on deposit would pay £25,000 a year in interest, so there would be no point taking the £20,000 a year. The lump sum would generate more. However, if interest rates dropped to only 1% then the large lump sum would produce little return at all. And inflation always affects the value of any amount of money, whether a lump sum or a periodical income payment.
Finally the tax position also affects how best to structure any financial ‘pot’.
The point of all this is that enough could simply be a guaranteed income. It doesn’t need to necessarily be a large lump sum.