If you've been diligently saving and investing for your retirement and have painstakingly built up a substantial nest egg, you'd hate to see bites taken out of it that you hadn't expected. Most us will be relying on our own savings for a significant chunk of our retirement income, and that money will need to last a long time.

After all, if you retire at 65 and live to 95, that's 30 years of retirement, and every dollar will be important. Here, then, are seven common expenses that can shrink your retirement savings -- before you retire and/or are in retirement. Learn more about them and aim to keep them to a minimum.

Hundred dollar bills in a whirlpool being sucked into a hole.

Image source: Getty Images.

No. 1: Healthcare

It's no surprise that healthcare costs can torpedo retirements. Fully 44% of retirees found that healthcare expenses in retirement were somewhat higher (27%) or much higher (17%) than they expected, per the 2018 Retirement Confidence Survey. So how much are we talking about?

A 65-year-old couple retiring today can expect to spend an average of $280,000 out of pocket on healthcare expenses over the course of their retirement, per Fidelity Investments -- and that doesn't even include long-term care expenses. A different report by the Center for Retirement Research at Boston College finds that, on average, retirees will face annual out-of-pocket healthcare expenses of $4,300 per year.

What you end up paying for healthcare in retirement isn't entirely under your control, but there are some ways to keep it in check. For starters, get fit and healthy and stay that way as long as you can because that can decrease your odds of developing costly conditions. Be smart about Medicare, too, choosing the plans that will serve you best.

No. 2: High-interest-rate debt

High-interest-rate debt, like you'll find in credit cards, can also sink you financially, whether you're in retirement or still years away from it. Many cards charge their holders interest rates of 20% to 25% or more. If you're carrying $20,000 in debt, that means you'd be forking over $4,000 to $5,000 annually -- just for interest. That money won't even be paying down your debt. That's money that could have helped your retirement nest egg grow or have been used in other productive ways.

Aim to pay off all high-interest-rate debt as soon as you can. (And by the way, you can do it -- many people have paid off massive debt loads.) As icing on the cake, when you make a payment against debt, you're essentially getting a guaranteed return on that money of whatever the interest rate is. So if you pay off $10,000 on which you were being charged 18% interest, it's like earning an 18% return -- because you won't have to pay 18% on that sum anymore.

No. 3: Fees

No matter what age you are, it's important to be aware of fees you're being charged -- by your banks, brokerages, credit cards, mutual funds, and more. As an example, consider mutual funds. The median expense ratio (annual fee) of stock mutual funds in 2017 was 1.18%, per the Investment Company Institute, with plenty of investors being charged even more than that. Meanwhile, broad-market index funds, such as those tracking the S&P 500, can be found with annual fees of 0.10% -- and even less.

The table below shows the effect of investing $10,000 each year over different periods and earning an average annual return of 10% -- while paying either 1.1% or 0.1% in annual fees.

Over this period

Growing at 8.9%

Growing at 9.9%

10 years

$164,663

$174,315

20 years

$550,920

$622,348

30 years

$1.5 million

$1.8 million

Calculations by author.

The difference a single percentage point can make is striking, costing tens of thousands of dollars over many years -- potentially even hundreds of thousands of dollars.

No. 4: Taxes

It's no surprise that you'll pay taxes in retirement, but you might be surprised to learn that your Social Security benefits may be taxed. Those benefits are generally not taxed, but taxation can rear its ugly head if your income over a year features not only Social Security benefits, but also significant other sources, such as wages, self-employment income, interest, dividend income, and so on. You'll never be taxed on more than 85% of your Social Security benefits, and if the benefits make up all or the vast majority of your income, you likely won't be taxed on them at all.

To determine whether you'll have to pay taxes on Social Security benefits, you need to calculate your "combined" income, which is your Adjusted Gross Income ("AGI") plus non-taxable interest plus half of your Social Security benefits. The table below shows the taxation you can expect:

Filing as

Combined Income

Percentage of Benefits Taxable

Single individual

Between $25,000 and $34,000

Up to 50%

Married, filing jointly

Between $32,000 and $44,000

Up to 50%

Single individual

More Than $34,000

Up to 85%

Married, filing jointly

More Than $44,000

Up to 85%

Source: Social Security Administration. 

If you're working late in life and don't need that Social Security benefit income while you work, you might do well to delay starting to collect it. That will increase your Social Security benefits. One way to manage that might be to draw more heavily from IRAs and 401(k)s in early retirement years if you're still working.

The question "Is your retirement at risk?" printed on a torn piece of paper, next to two red dice.

Image source: Getty Images.

No. 5: Your mortgage

It's imperative to shed your high-interest-rate debt, as noted above, but even low-interest-rate debt can be burdensome in retirement when you'll probably be living on limited income. If possible, aim to enter retirement after you finish making mortgage payments. As a homeowner, you'll still have home-related expenses to face, such as property taxes, home insurance, maintenance, and repairs, but you'll likely feel freer and more financially flush once your home is paid off.

Speaking of mortgages, if money is particularly tight in retirement, you might want to consider a reverse mortgage. With a reverse mortgage, a lender will provide a stream of (often tax-free) income and the loan doesn't have to be paid back until you no longer live in your home -- such as when you move into a nursing home or die. It has some drawbacks, though, such as requiring your heirs to sell the home unless they can afford to pay off the loan. Still, if you need additional income in retirement and no one is counting on inheriting your home, it can be a solid income solution.

No. 6: Your kids

Your children may bring lots of joy in life, but they can also wreck your retirement. Fully 4 out of 5 parents offer some financial support for their adult children, according to a survey from Merrill Lynch and Age Wave -- spending twice as much on their kids as they do on retirement savings. A TD Ameritrade survey found that, on average, millennial parents received about $11,000 annually (in money and unpaid labor) from their own parents.

It can be hard to say no, of course, or to watch your grown children struggle. But if you're sending, say, $10,000 to your kids each year, you're short-changing your retirement coffers. That sum, if it grew at an annual average rate of 8%, would amount to more than $156,000, a most welcome sum in retirement.

One way to avoid this scenario if your kids are still young is to make them financially savvy as they grow up. Share your personal money-management processes and thinking with them regularly -- perhaps by having them watch you pay bills and think through a big purchase. Get them to appreciate the power of compounded growth and start them investing in some stocks while they're still young, too. With any luck, they'll eventually be in a position to help you in retirement -- or at least not to need any of your money.

No. 7: The unexpected

In retirement and also at any time before it, unexpected developments can wreak havoc with your finances. A 2015 report from the Pew Charitable Trusts found that fully 60% of American households "experienced a financial shock" over the previous year, with about a third of them experiencing two. The median cost of households' most expensive shock was $2,000, or about half a month of income, and more than half of households had trouble making ends meet after experiencing their shock.

If you're in retirement and you have a stockpile of money to support you, you may find that you just tap that fund for unexpected major car repairs or other sudden needs. Be careful, though, that you don't render your nest egg insufficient to support you for as long as it may need to.

A good defense against being sidelined by unexpected financial needs is to have an emergency fund, ideally funded with six to 12 months' worth of living expenses, such as for food, rent or mortgage payments, utilities, taxes, insurance, transportation, and so on. It can be part of your overall nest egg, but make sure that it's easily available if you need it and doesn't require the liquidation of stocks that may have temporarily fallen in value or cashing out a CD prematurely and facing penalties.

Just as it's critical to plan for your future by figuring how much money you'll need in retirement and how you'll get it, you also need to brace yourself for and defend against the expenses above that can eat into those savings.

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