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If you're getting into the latter part of your career, retirement is probably on your mind quite a bit. However, retirement can be scary – especially from a financial perspective. With that in mind, here are four of the most common personal finance questions asked by pre-retirees and how to find the best answers to them.

When is the best time to take Social Security?

You can choose to start collecting Social Security anytime between the ages of 62 and 70. And there are a few things you need to consider before you can decide the best age for you.

First of all, the longer you wait, the higher your monthly Social Security benefit will be. If your full retirement age is 66, starting benefits at 62 results in a permanent reduction of 25%, while waiting until 70 increases your benefit by 32%.

However, the reason for the permanent increase or reduction is because it's theoretically all the same. In other words, the average retiree should receive the same total lifetime benefit, no matter when they choose to start. Of course, there are a lot of variables here -- for example, if you're in particularly good health, it could work out in your favor to wait. Or, if you lose your job or otherwise need the money, it could be a good idea to claim early.

Here's an article with a thorough discussion of the pros and cons of various Social Security claiming ages to help you make your choice.

Do I have enough money to retire?

It's not necessarily about how much you have in the bank. Rather, it's about creating enough income after retirement to provide the lifestyle you want.

You need to consider income from all sources. Between Social Security, any pensions or annuities you may have, and your retirement savings, it's a good rule of thumb to expect to need 80% of your pre-retirement income after retirement in order to maintain your lifestyle.

As an example, let's say that you and your spouse earn $100,000 per year, which implies a retirement income need of $80,000. After looking at your Social Security statements by creating an account at www.ssa.gov, you determine that you can expect a combined $2,500 per month in Social Security income, or $30,000 per year. This implies that you'll need $50,000 from your savings.

Based on the often-used 4% rule of retirement, this means that you'll need a nest egg of $1.25 million to be able to produce $80,000 per year in total income. Granted, the 4% rule isn't perfect and there are a bunch of variables that could make your income need higher or lower, but this is a good general benchmark.

Do I need to sign up for Medicare?

For some people, this is the easiest question of all. If you're already getting Social Security retirement or benefits before you turn 65, or you've been getting disability benefits for at least 24 months, you'll automatically be enrolled in Medicare, with coverage beginning the first day of the month you'll turn 65.

If this doesn't apply to you, you'll need to sign up. You'll have a seven-month initial enrollment period, beginning three months before the month of your 65th birthday. While you don't need to sign up right away, not doing so can result in permanently higher Medicare premiums.

If you're planning to retire later than 65 and are covered under your employer's plan, it gets a little trickier, depending on whether your employer requires you to sign up right away. If they don't, you'll get a special enrollment period once you leave your job and you won't be penalized. Here's a thorough look at what you should know about Medicare before you retire.

What should I do with my 401(k)?

When you retire, there are three basic options for money in your 401(k) or similar retirement plan.

1. Cash it out -- If you're over 59 1/2 or are over 55 and have left your job, you are free to withdraw as much money as you'd like from your 401(k) without penalty. However, unless yours was a Roth (after-tax) account, keep in mind that the money you withdraw will be treated as taxable income. If you take the entire amount as a lump sum, it could easily catapult you into a high tax bracket for this year. On top of that, you'll be depriving yourself of future investment gains.

2. Leave it alone -- As long as your account balance is greater than a certain threshold (generally $5,000 or so), you can leave the money in your employer's plan. It will stay invested according to your allocation selections, and you can withdraw from the account as you see fit.

3. Roll it over -- You also have the option to roll over your money into another qualified retirement plan, such as an IRA. This can be preferable for a few reasons. First, you'll have a much better selection of investments. IRA assets can be invested into any stocks, bonds, or funds you want. And if you have retirement assets in several places, such as 401(k)s from several employers, this can allow you to consolidate your savings in one account.

Learn all you can

The best thing you can do before you retire is to learn as much about these and other relevant personal finance topics before you're ready to leave your job. Check out some of the links contained in this article as well as other content. The more you know, the better equipped you'll be to deal with whatever financial challenges retirement throws at you.