To me, I would probably be content with 500k that is probably invested in shares with a bit of liquid cash available in there. That would allow me enough freedom to choose whether to work or not, cover any expenses and gradually pay down the mortgage and cover regular expenses like household bills and even budget holidays. That would be enough to keep me content in life, but I'd probably still go to work just for the challenge and extra social interaction is brings - but not look for anything that is too stressful because it can effect your quality of life negatively. Some people think a million or a hundred million is necessary to be rich, but it's how well you utilize the money you have that counts.