This post first appeared on Forbes.com.\r\n\r\nThis summer, you have one of the best opportunities to fine-tune your portfolio. In fact, you could potentially add tens of thousands of dollars to your 401(k) and IRA balances come retirement time.\r\n\r\nThe catch: You must be willing to step up and pay attention closer attention to the fine print. Your 401(k) is now required to disclose the investment and administrative fees you pay to participate in your plan.\r\n\r\nI can hear the question in your head:\u00a0What fees?\u00a0You\u2019re not alone.\u00a0An AARP survey found that 70 percent of 401(k) participants weren\u2019t aware there are fees embedded in their 401(k) that are reducing their net performance. If it makes you feel any better, the General Accountability Office did its own survey of the folks sponsoring 401(k) plans \u2013 your employer \u2013 and also discovered an alarming lack of awareness of fund fees.\r\n\r\nThat\u2019s a potentially costly lack of awareness. All 401(k) plans charge two broad sets of fees. The biggest chunk goes toward investment fees. The thing is, you won\u2019t ever see a line-item \u201cinvestment expense\u201d in your 401(k) statements. The way it works is that these fees are bundled into what is known as an \u201cexpense ratio\u201d \u2013 a percentage of a fund\u2019s net assets \u2013 that is deducted from every mutual fund\u2019s gross returns. What you see in your 401(k) statement is net returns after subtracting that fee.\r\n\r\nSo for example, let\u2019s say a fund you\u2019re invested in generates an 8 percent gross return. You won\u2019t have 8 percent credited to your account. First the expenses are deducted. If the expense ratio is 1.2 percent, the net gain credited to your account will be 6.8 percent. If the expense ratio is 0.50 percent, the net gain credited to your account will be 7.5 percent.\r\n\r\nSound like small potatoes? Well, if you\u2019ve got $100,000 today that will earn an annualized 6.8 percent for the next 25 years you\u2019ll end up with about $518,000. If that $100K compounds at an annualized 7.5 percent you\u2019re looking at having close to $610,000. That\u2019s nearly a six-figure pick up solely because you paid attention to fees. Not exactly small potatoes, right?\r\n\r\nThe good news is that your 401(k) is required to do a better job showing these fees. But all they have to do is disclose the information. It\u2019s up to you to use that information to your advantage.\r\n\r\nUnfortunately, it seems many people aren\u2019t taking notice. Some 401(k) plans that already share this information with participants report there hasn\u2019t been much response. That\u2019s not exactly shocking \u2013 inertia is one of the most prevalent enemies of investors \u2013 but it is incredibly disappointing.\r\n\r\nGiven the endless stream of surveys reporting how worried Americans are about their retirement security, it seems to me you can do yourself a great favor. Pay attention to the new fee disclosures required of 401(k) plans. Here are a few ways to use the new fee disclosure to boost your retirement balances:\r\n1. Size up what you\u2019re paying\r\nOne of the disclosures you will receive is a laundry list of the charges for the investments offered in a plan. Yes, you\u2019re captive to the funds offered in your plan, but if you discover one or more of the funds you\u2019re investing in is a fee hog, time to rethink.\r\n2. Focus on the low-cost options\r\nWhile it\u2019s vitally important that your overall long-term retirement portfolio be well-diversified, there is no reason that your 401(k) has to be a paradigm of diversification. If you have other retirement accounts \u2013 IRAs, rollover IRAs, taxable accounts you will use for retirement \u2014 the goal is that all those pieces mesh together into one cohesive allocation strategy. Don\u2019t worry about the diversification within each piece. That means you could take a look at your 401(k), find the lowest cost option and load up on that asset within your plan. Then adjust your other retirement accounts accordingly.\r\n3. Keep investing even if it\u2019s a fee dog\r\nOkay, if you discover your 401(k) plan lacks any low cost funds, keep contributing if your plan gives you a matching contribution. Set your contribution rate to capture the maximum match, but don\u2019t contribute more. Then after you\u2019ve received the max match \u2014 or if your plan doesn\u2019t offer a match \u2013 focus on saving in an IRA. The maximum IRA contribution this year is $5,000 if you are under age 50; older workers can contribute $6,000 this year. The advantage of an IRA is that you set it up at any mutual fund or brokerage firm where you can choose among thousands of investment options, including low-cost exchange-traded funds.\r\n\r\n4. Look for low-cost index funds.\r\nReams of research show that the majority of funds that are actively managed fail to consistently beat index funds that simply aim to track a market benchmark. Sure there will be outliers that manage to thump an index for maybe a year or two or three.\r\n\r\nBut today\u2019s hot hand typically cools over time.\u00a0Moreover, your portfolio is no doubt comprised of a handful of funds focused on different asset classes. You really think you can nail the outlier four or five times? C\u2019mon. Low-cost index funds should be the core of every 401(k) account. (I\u2019d actually\u00a0love to see more funds add exchange traded funds \u2014\u00a0ETFs\u00a0\u2014 which can be even cheaper than index funds.)\u00a0And those funds should\u00a0have expense ratios below 0.50 percent. There are plenty of index funds charging less than 0.10 percent, so I am being\u00a0generous with a rule-of-thumb of 0.50 percent. Broad market index funds charging 1 percent are just a flat out bad deal you\u00a0should howl about. Which brings me to my next point\u2026.\r\n5. Let H.R. know you\u2019re on the case\r\nLet\u2019s face it, the folks running your company are probably more focused on growing revenue than fine-tuning the 401(k). That said if enough of you speak up that can spur change. And keep in mind that GAO report I mentioned earlier: plan sponsors didn\u2019t exactly show a whole lot of comprehension about how their plan worked.\r\n\r\nThe new federal regulations require plans to get better disclosure. Chances are your employer may be learning a ton along with you. That\u2019s an opportunity to chime in about what changes you want. You might want to slip in the phrase \u201cfiduciary duty\u201d\u00a0into the conversation. That\u2019s the fancy way of saying that every 401(k) plan must be run for the benefit of the participants.\u00a0Low(er) fees certainly qualify as one way a plan can fulfill its fiduciary role.\r\n6. Get out of old expensive 401(k)s\r\nWhile you are a captive participant in the plan of your current employer, any 401(k) from a prior job can be moved to what is known as an IRA rollover.\u00a0If you are voluntarily still investing in an old 401(k) with costly funds, move the money ASAP to a fund company or discount\u00a0brokerage. There\u2019s no tax due when you make the move\u2014assuming you follow some basic rollover rules every financial\u00a0institution will be happy to help you with. Once the money is in your Rollover IRA account you can then invest in any funds, or\u00a0stocks or ETFs you\u2019d like. You are free to put together a solid low-cost portfolio.\u00a0 That\u2019s one of the few slam-dunk ways to\u00a0boost your account balances come retirement time.