So you’ve accepted a lucrative position at another company within your industry. Perhaps you’re in the middle of a career change. Maybe you’re uprooting and heading to greener pastures somewhere else. Whatever the reason, you’re changing jobs. Out with the old, in with the new.

Amidst the hassles of moving, finding the kids a new school, and settling in to your new position and community, it’s easy to lose sight of the finish line—retirement. Your 401(k) is probably your most important investment in regards to retirement savings. Don’t let it get lost in the shuffle when a change in your professional life comes along.

When switching jobs, there are three things you can do with your existing 401(k): leave it where it is, roll it over into an account with your new employer, or move the money into an IRA. Cashing out the plan is not an option. We repeat: DO NOT CASH OUT YOUR 401(K)! It’ll badly set back your retirement savings plan. You’ll be hit with income taxes plus a penalty of 10 percent if you’re under age 59½. What’s more, you’ll miss out on tax-deferred savings.

Leave It Where It Is

There’s nothing wrong with keeping the cash where it is if you’re happy with the plan at your old job. If you’re confident you can keep track of it, if you’ve got a nice chunk of change in there, or if the plan your new employer is offering is less than appetizing - leave it be. Just make sure you tell your old HR department about your plan to leave it behind. If there is less than $5,000 in the account, they have the right to dump you.

Roll It Over

Most financial professionals agree it’s a good idea to have all of your 401(k) dollars under one roof. It’ll work harder for you as one asset and you can dip into it (as a loan) if a financial emergency arises. If you do decide to rollover, make sure to jump through all of the (relatively minor) hoops and fill out the appropriate paperwork with both your old company and your new employer.

Drop It Into An IRA

If your new gig doesn’t offer a 401(k) program, or if you dig the investment freedom that comes with an IRA, go this route. You’ll have much more of a choice when it comes to investing your retirement dollars, as thousands of mutual funds will be at your behest instead of a dozen or so 401(k) options. Be cautious when going this road, though. 401(k)s are generally a smidgen more protected from those evil creditors than are IRAs. It’s a minor detail now, but if you ever declare bankruptcy or get sued, it could become a much bigger issue.

Whichever route you choose, know the rules. Way back when, details were cloudy on the IRS-friendly way to transfer funds from one 401(k) to another account. Investors had to put 401(k) funds into a “conduit” IRA if they believed they would move the funds into another 401(k) account in the future. The money couldn’t be mixed with other retirement savings and new contributions were also verboten. Sound confusing? It was.

But no longer. Mix all you want. You can transfer an old 401(k) account into an IRA while still making payments, move it from a new IRA into a Roth IRA, or shift the funds directly into a new 401(k) account. The choice is yours.

However, make certain to complete a “trustee-to-trustee transfer” when you relocate your funds. This basically means you’re directing your new employer to schedule the details of the transaction with your old company. This way, you can avoid your old job writing you a check for your existing 401(k) balance, wherein you have 60 days to drop it into a new account. This is not a headache you want. When you go this direction, your previous company will hold back 20 percent of your money for income tax purposes.

The next time you file your taxes, you’ll get the money back, but meanwhile you’ll have to make up the difference yourself within the 60 days. No thanks. Even more frightening: if you don’t roll over the entire balance within 60 days, the taxman cometh. The IRS sees that deficit as a taxable withdrawal and enforces regular income taxes along with a 10 percent penalty.