One expense that should be factored in: retirement savings for the nonworking spouse. "That's a big mistake people often make when they get out of the work force. That could really cause problems (later)," says Kimberly Palmer, the author of "Generation Earn: The Young Professional's Guide to Spending, Investing and Giving Back."

Suppose you do manage to live on one paycheck during the trial period. What to do with the second income? Bank it, of course. It becomes your emergency fund. (Already have such a fund? Well, now you have a larger one.)

Step 4: Look for other ways to make money

If you can't get unemployment and nothing's available in your field, consider selling belongings, taking a stopgap job or even creating your own work. Spicer did freelance computer consulting, sold off his company's construction equipment and, over time, short-sold most of the properties. Carolina marketed many of their personal items online, which Spicer now says was a good move because it reduced clutter.

The biggest change, though, was Spicer's creation of SkyLedger, a Web-based accounting system he designed from software he'd previously developed for his own business. SkyLedger has become a full-time job, and he continues to work as a computer consultant.

Jaime did a little freelancing (managing a video project for friends) when Finley was 6 months old. By 2008, she had started in a new field, business coaching. She worked briefly at a local company, but when the hours got too long she decided to work from home. Jaime blogs about successful business and life strategies at Eventual Millionaire, but this does not bring in extra income, as she decided against putting ads on the site.

Step 5: Communicate -- and perhaps reconfigure

This isn't the last step, but rather a continuation of Step 1. It's essential to keep talking about what's going on, both financially and emotionally.

"People assume their partners have the same dreams, or at least expectations. But they seldom do," says Herigstad.

Sometimes those assumptions are internalized. Matt Tardy says that, early on, Jaime sometimes felt bad about being a full-time mom instead of wage-earning one. "I had to say, 'Whoa! That's not why we're doing what we're doing.' It's just hard for the other person to feel like they're contributing if they're not contributing financially."

Personal finance author Kay advises having a weekly money talk -- and to talk about finances only then. If a disagreement comes up, "shelve it until Money Night," Kay says. And if you're either planning to downsize or facing job loss, start your Money Nights now.

How are our two couples doing?

Jaime and Matt currently make between $70,000 and $80,000 a year. They pay extra on the mortgage, fund their own retirements, have zero debt and try to put at least $1,000 a year into college funds for their two kids (daughter Jet was born in May 2009). Recently they paid cash for a used vehicle. They no longer use credit cards.

Spicer and Carolina still have about $1 million in business-related debt. Carolina finished her master's degree in early childhood education in May 2010 but hasn't been able to get a job; she has been substitute-teaching fairly often, though. Spicer works seven days a week, for SkyLedger and as a computer consultant. Between them, they earn about $75,000 per year. Spicer is putting $200 a month into a Roth IRA, but they haven't started one for Carolina yet, having hoped she'd get a teaching job with a decent retirement plan. Financial turmoil has kept them from starting a family.

Sometimes the downsized life is temporary. You live simply while you find a new job, raise kids or make a success of your new business. But once those things happen, some decide they like a simpler lifestyle.

"Yes, we're on a tight budget, but we're making a little bit more every year and that's exciting," Jaime says, "because you can save."

"If you can have a more enjoyable tomorrow because of a little pain today, I'm OK with that."

Save money today

Fee free: The "Do One Thing" series at Bundle wants to save you money. "Never pay another late fee" shows both paper people and e-payers how to organize.

Avoiding temptation: Have a spending problem? "Don't put yourself in these situations" offers a very basic (and funny!) piece of advice.

Donna Freedman is a freelance writer in Seattle. You can find more of her writing on MSN Money's Frugal Cool blog and at Surviving and Thriving (motto: "Life is short. But it's also wide.").