BOSTON — Not so long ago, Americans retired debt-free. Then, somewhere along the way, that changed. Now more and more Americans are retiring with debt, with mortgages, with home-equity lines of credit, with credit-card debt, with auto loans and more.

Before the great recession of 2008-09, that debt — while not insignificant — didn't seem to be a huge problem.

"Important measures of financial vulnerability suggest that the growth of debt might not be that worrisome," Mauricio Soto wrote in a 2005 Center for Retirement Research at Boston College report. "The combination of extraordinary asset growth and historically low interest rates allowed households to increase their debt relatively painlessly: their net worth grew significantly, and the portion of income used to pay for debt did not increase."

"This is not to say that baby boomers might not encounter a few bumps in the road or that some groups might not be vulnerable. But baby boomers as a group do not appear to have an immediate debt crisis," he wrote.

That was then and this is now. And now it's not just a bump in the road; the road has seemingly disappeared. The debt load of would-be retirees and retirees is worrisome. Consider: One in five (22 percent) boomers owe at least $50,000 in non-mortgage debt in 2009, up from 12 percent in 2007, according to the just-released "Debt: The Detour on America's Road to Retirement," Securian's 2009 Survey of Financial Values and Debt.

And nearly four in 10 baby boomers had non-mortgage debt of $25,000 in 2009, 29 percent in 2007. Equally troubling, the percent of those in the so-called "silent generation," the boomers' parents, with debt of $25,000 or more was 22 percent in 2009, the same as in 2007.

The great recession of 2008-09 has changed the behavior of many boomers, according to Kerry Geurkink from Securian. Americans, in general, are less likely to view debt as a way to fuel their lifestyle, are saving more for emergencies and looking for ways to save on groceries, transportation and the like. They are paying off car loans, credit-card bills, mortgages, home-equity loans, overdue bills, money owed to family or friends, and other debts.

But boomers are not. "Few are actively paying down their debt," according to Securian's report. Yet "most expect to have fully eliminated all non-mortgage debt within the next five years." And while that might seem a pipe dream, boomers aren't smoking dope when it comes to understanding that their debt will affect their ability to have a comfortable retirement.

By the way, Geurkink says your non-mortgage debt is an indication of just how much beyond your means you might be living.

So what's the takeaway here? In short, boomers must and should make retiring debt-free, even mortgage-free, a priority. And they must do that while making sure they have saved enough for retirement. "Retiring debt-free should be the goal for more Americans," Geurkink said.

But how? Here are four suggestions:

1. SET UP A PLAN

In his book, "The Complete Idiot's Guide to Getting out of Debt," author Ken Clark talks about the need to change your lifestyle and spending habits, the need to start today and the need to set realistic goals. But Clark doesn't want this to be too painful. In his book, he suggests rewarding yourself along the way. He suggests treating yourself every time you eliminate a piece of debt.

His other piece of advice is to partner with someone who wants to get out of debt too, someone to whom you would be accountable for your debt-reduction plan.

2. PAYING DOWN DEBT VERSUS SAVING FOR RETIREMENT

Experts have different opinions on this one. But Geurkink suggests that you do both at the same time, pay down your debt while saving for retirement. No doubt that could lengthen the time it takes to pay down your debt, but it will at least create two habits — one of saving and one of paying down debt.

"You have to do both," said Geurkink. "Something changes when you start adopting a savings habit. When you accumulate money, your mindset changes, you start thinking like an investor rather than someone prone to impulse purchases."

Others suggest that you pay down your debt first, sacrificing your retirement nest egg if only till you get yourself back on track. By paying down your debt, you know exactly what rate of return you are getting on your money — the interest rate the debt carries. By investing, at least in the stock market, you don't know what your rate of return might be.

There is, however, at least one exception to this rule of thumb, according to Clark. If you participate in a 401(k) with a match you might as well contribute to the match and then slot your remaining dollars toward paying down your debt. After all, he said, it's hard to get a better return than a 401(k) match. "It's free money," he said.

Make no mistake about it, though: Paying down credit debt, if that's what you have, could either take awhile or it could limit your ability to save for retirement. According to Bankrate.com's debt reduction calculator, for instance, you would have to pay $432 per month over the course of five years to pay down $15,000 in credit-card debt that has a 24 percent interest rate. Or you could pay $1,000 per month and eliminate that same credit card debt in just 19 months.

So let's say you chose to do both: Pay down $432 per month for five years and save $600 per month over the same period. You would be debt-free and have $40,803 set aside in your retirement account, assuming a 5 percent rate of return.

By contrast, let's say you decided to pay down your debt first and then save $1,000 a month: You would have $44,609 in your retirement account, by my rough calculation.

Clearly the latter is the better deal, but it does mean being both aggressive about paying down your debt, changing your lifestyle and then making sure you start saving on a regular basis. When in doubt, many behavioral finance experts suggest putting the two habits on autopilot. And giving up $4,000 or so just might be the price you have to pay.

3. DON'T BORROW FROM YOUR 401(K) TO PAY DOWN YOUR DEBT

It might seem like a good idea at first blush, but many experts say borrowing from your 401(k) to pay down your debt might not be in your best interest. Yes, it's a low-cost loan. But borrowing money from your 401(k) could create even more problems should you get laid off from your employer. Typically, you have to pay loan off within 60 days of leaving your employer.

4. WORK LONGER

There's no doubt about it, according to Geurkink. If you plan to retire with debt, especially non-mortgage debt, you may put yourself in a bind. Living on a fixed income and servicing debt is a recipe for disaster. Instead, Geurkink suggests working, full-time or part-time, for as long as you can until you eliminate your debt. Once you eliminate your debt, then you can retire.