“Fidelity Investments analyzed the savings habits of roughly 1,100 401(k) investors who earned less than $150,000 a year and had accumulated more than $1 million in 401(k) savings to determine how they reached the million-dollar mark.
The retirement plan provider found these savers, who were an average age of 59, had some key behaviors in common: they started young, always took advantage of the company match and saved a large chunk of their pay each year, a median of 14% (not counting the company match).” See 401k millionaire