At CNNMoney, Walter Updegrave hosts an “Ask the Expert” column in which he fields reader questions. (Updegrave is an editor at Money Magazine.) Lionel from San Diego recently wrote in with a question that all of us have:

What percentage of income should someone save in order to be considered financially responsible? I’m wary of spending now because of the bad economy, but I don’t know how much I should be saving on a monthly basis.

This is a great question, and something I’ve wrestled with over the past year or two. Ultimately, I decided to embrace Elizabeth Warren’s balanced money formula, which says to set aside at least 20% of after-tax income for Savings, keep Needs below 50%, and use the rest for Wants:

In other words, my target savings rate is 20% of my income. My wife tries to save 25% of her income. We’ve structured our lives to make this possible. But what does money expert Walter Updegrave recommend? First he notes that Americans aren’t exactly savers:

When it comes to socking away bucks for retirement, the National Foundation for Credit Counseling’s 2009 financial literacy survey also shows we’re not exactly knocking ourselves out. About a third of those polled said they put away nada for retirement, another third save 1% to 10% and just under a quarter save more than 10%. (The rest said they didn’t know how much they set aside or refused to answer.)

But then Updegrave gives a great answer, which boils down to: Do what works for you. There is no right answer to this question. Each of us is in a different situation, and while it might be financially responsible for me to save 20% of my income, for you that number might only be 5%.

Updegrave says that it’s not important what percentage of your income you save, but that you develop the habit. Build an emergency fund. Develop a retirement savings regimen. When you’ve done these two things, look for a additional ways to save. Most of all, he says, don’t make excuses. We all have things we’d rather spend our money on; if your goal is to be financially responsible, make saving a priority.

Note: Flexo at Consumerism Commentary recently wrote about Updegrave’s advice as well.

[CNNMoney: 3 steps to financial security: Save, save, save]

This article is about Basics, Choices, Retirement  Thursday, 7th May 2009 (by J.D. Roth)