When you're thinking ahead to retirement, you probably visualize spending your money traveling to see the world, indulging your hobbies, and perhaps spoiling your grandkids.

Unfortunately, there are some big expenses you'll likely get stuck with as a senior that may not be on your radar. These costs aren't for fun things, they aren't optional, and you need to have a plan for paying them. If you don't, you could run through your retirement savings much more quickly than anticipated and could find yourself in financial trouble.

What are these big expenses you need to consider when preparing for retirement? Here are three of them. 

A laughing senior man carrying a young boy on his shoulders.

Image source: Getty Images.

1. Taxes

Unless you have Roth accounts, you're going to be taxed on distributions you take from your retirement investment accounts. In most cases, you're taxed on distributions at ordinary income tax rates. This means you lose a big percentage of your distribution to cover the costs of taxes -- with the specific amount you lose depending on your tax bracket. A single tax filer with a taxable income of $39,475, for example, would end up with an IRS bill of $4,543 in the 2019 tax year

Depending on your taxable income, you could also be taxed on up to 85% of your Social Security benefits. The federal government taxes most pension income, while some states impose state taxes on pensions and Social Security benefits as well. This guide to how your retirement benefits are taxed can help you figure out what you might owe to the IRS and to your state as a retiree.

Unfortunately, if you forget about taxes, your retirement nest egg may seem much bigger than it actually is. If you have $500,000 saved and plan to follow the 4% rule and withdraw 4% of your savings in your first year of retirement, remember that $20,000 withdrawal from your 401(k) won't actually give you $20,000 to spend after taxes are taken out. 

To make sure you have enough saved, figure out what your after-tax retirement income will be, given your Social Security benefits, savings, and other sources of income. If you can't afford to live comfortably on that income, you'll need to look for ways to increase it -- such as saving more or delaying claiming Social Security. Or, you may need to look into a move to a state that's more tax-friendly for retirees

2. Healthcare

Once you turn 65, Medicare is going to pay for all your care -- right? Unfortunately, while many seniors mistakenly believe this is the case, it's simply not true. Medicare doesn't cover many kinds of care, including dental care, eye exams and glasses, and hearing aids. Medicare prescription drug coverage also has lots of gaps that could leave you responsible for covering a significant percentage of your medication costs.

And even when Medicare does cover you, there are Medicare premiums and coinsurance costs to pay, which can add up quickly if you have a hospital stay or need other expensive care. Chances are good you'll want a Medigap or Medicare Advantage Plan to expand on traditional Medicare coverage, but these plans also come with additional premiums. 

All the medical expenditures you're likely to incur as a senior can add up to a much larger sum than you expect. In fact, Fidelity estimated a 65-year-old couple retiring in 2018 would need around $280,000 to cover care costs. And, thanks to healthcare inflation, things are only going to get worse. 

To make sure you've got the funds, you'll need dedicated savings for healthcare expenditures. If you have a qualifying high-deductible health plan during your working years, investing in a Health Savings Account (HSA) is the best way to build this savings because you can make tax-deductible contributions and won't pay taxes on funds withdrawn to cover care. But if you're not eligible to make HSA contributions, you still need to save additional funds in your 401(k) or IRA that are earmarked for medical care during your senior years. 

3. Long-term care costs

Finally, you need to figure out what you're going to do about covering long-term care costs if you or your spouse need nursing home care or home healthcare services. Medicare provides no coverage for long-term care costs if you need custodial care, which is basic routine nursing care. Someone turning 65 today has a 70% chance of requiring long-term care of some type before passing away. 

Long-term care costs a literal fortune. Genworth Cost of Care survey estimated the median cost of a home health aide in 2018 was $4,195 monthly, while the median cost of a private room in a nursing home is a whopping $8,365 per month. If your spouse has to go into a nursing home and you need to pay more than $100,000 a year for it, what's that going to do to your retirement nest egg?

Having a plan to cover these costs is essential before you consider leaving the workforce. This could mean buying long-term care insurance; working with a lawyer to make a Medicaid plan to protect your assets so Medicaid covers your nursing home; or simply saving a whole lot of money in case the day comes when you or your spouse will need nursing care. 

Planning is key

Saving money for healthcare, accounting for taxes when evaluating your 401(k) balance, and making a plan to cover long-term care costs is essential if you want true financial security as a senior. Start planning for these expenses today, because the younger you are when you put your plans into effect, the more likely it is you'll end up with the cash you need to cover these big expenses as a retiree.