With fine watches, fine cars, fine holiday homes to be bought in exotic locations, kids, education, house maintenance, wife, jewellery, good food, new technology, higher prices of energy, new gadgets, clothes, booze (better and better varieties) , TAXES and what not , forever on the increase... its tough to decide a figure that would be enough....
To me it looks like, nothing is enough, because for each leap in wealth, newer expenses attach to you and one even forgets how he got along before he had the new wealth..