Today’s workers are most likely to depend on a 401(k) plan to fund their retirement. To help your 401(k) grow, avoid these 10 mistakes.The first is failing to calculate your retirement needs. Most advisors recommend an income of 70-to-90% of your pre-retirement income. Online tools can help you figure out how much you need to save. Second is leaving money on the table. Make sure you contribute enough to qualify for the full amount of your employer’s matching contribution, if your employer makes one. Third, saving at the default contribution level. That can be as low as 2 or 3%, but it’s best to contribute 10-to-15%. Fourth, failing to research your investment options. About a third of Americans in a 401(k) don’t do any research of their own. Fifth, missing out on free investment advice. Employers are required to provide it, and research shows most who follow it will benefit. Sixth, avoiding risk completely. Safe investments like money market funds and CDs don’t grow as fast as inflation. One approach is to subtract your age from 110. The answer you get is the percentage you should allocate to stocks. If you’re 30, 80% of your 401(k) should be in stocks. Seventh, failing to rebalance your 401(k) to preserve growth and manage risk. Eighth is borrowing from your 401(k). You have to pay it back or face penalties and heavy taxes. Ninth is cashing out your 401(k). If you leave your job, the best option is to roll your 401(k) into an IRA. And 10th, abandoning your 401(k). When you leave the company, take it with you by rolling it into an IRA or a new employer’s plan.