Is a second household income worth it?(Knight Ridder Newspapers)

Byline: Cindy Krischer Goodman

MIAMI _ Even as Bertha Martell hand-washes and irons her husband's work shirts to save money on dry cleaning, she still contemplates whether she will have to go back to work in the fall as a teacher to make ends meet. Martell, a mother of four, will again have to figure out whether it pays for her to work.

It's a calculation that many people in and out of the workforce make. But some of us are so busy commuting, dropping off kids at day care and trying to please the boss that we fail to do the basic math to see whether all the effort is worth it.

As the economy sinks deeper and job layoffs continue, it just might be time to figure things out. In some cases, when you look at how much money a second wage earner brings home and take into account what he or she spends to earn it, the outcome is that the second income just doesn't pay.

Cleary, every family differs in how much its working members earn, the number and age of dependents (including elderly parents), spending habits and the motivation for working. Many South Floridians squeak by on minimum wage and work just to put food on the table, while others work because both parents enjoy their jobs.

But most people work because they think they can't afford not to.

Financial experts say although every family's financial portrait differs, if the second income earner grosses less than $30,000 a year, the family might be better off with that spouse at home.

Consider this example: From a $30,000 annual salary, subtract $9,300 in income taxes. Next, take out $1,200 for work clothes and dry cleaning and $3,000 for dining out, lunches and fast food. Then subtract $3,100 in home maintenance, repairs and housekeeping that dual-career couples often pay someone else to do.

Now, take off $2,500 in …