The wealth of households amounts to US$280 trillion (2017). According to the eighth edition of the Global Wealth Report, in the year to mid-2017, total global wealth rose at a rate of 6.4%, the fastest pace since 2012 and reached US$280 trillion, a gain of US$16.7 trillion. This reflected widespread gains in equity markets matched by similar rises in non-financial assets, which moved above the pre-crisis year 2007's level for the first time this year. Wealth growth also outpaced population growth, so that global mean wealth per adult grew by 4.9% and reached a new record high of US$56,540 per adult. Tim Harford has asserted that a small child has greater wealth than the 2 billion poorest people in the world combined, since a small child has no debt.
If you have 20 years left to live and only require $60,000 a year, having $1,200,000 can also be considered enough even if you make zero return. The only problem is that your purchasing power will decline by ~2% a year due to inflation. The other problem is that you don’t know exactly how many years you have left to live. Therefore, it’s always better to have more rather than less.