Key Takeaways Only 14% of participants contribute the annual maximum in Vanguard-run defined contribution retirement plans, such as 401(k)s. High-income earners are more likely to max out their 401(k)s, but even if you have a modest income, you can reach this goal. The power of compounding returns means you have a strong incentive to save as much as possible, as soon as possible. The reality of the U.S. retirement system is that most workers chronically under-save. Just over one-third of non-retir ...