NEW YORK (CNN/Money) – Whenever someone asked me what I wanted to be when I grew up, I often would joke and say, "Philanthropist."

I meant, of course, being independently wealthy with nothing more worthwhile to do than give away my money to charities I championed.

What I definitely didn't mean was being some kind of toll-paying Trina who anyone with a cause feels free to hound for money.

And yet, judging from the perpetual beg-a-thons that we encounter in our everyday lives, that's how many of us are viewed. When I open my mail, answer the phone, show up at work or make my way home, there's often a request for money.

The problem, of course, is that when you're a toll-paying Trina (whose funds are less ample than those of, say, malaria fighter Bill Gates) you usually don't apply a systematic rationale to giving. You give based on how you feel at the moment or based on who's asking. For instance:

You give to relieve yourself of guilt. You might tell yourself: "I've been fortunate. I should make a donation, even if it's not a lot. Every little bit helps. At least now I can feel like I'm doing something."

Or you give so that you're not thought of as a cheap, cold-hearted jerk. This might be a good time for everyone with a well-funded alma mater -- where they've already paid good money to attend -- to reprise their school's favorite fight song.

Or you give because you have to. Your boss or the chairman of your company may recommend you fork over some cash to his or the company's favorite charity.

In any case, you're not always giving because you want to, or because you believe in an organization -- or even know anything about it.

Here's just one example: I was recently asked by a generous-hearted colleague if I wanted to contribute money to an orphanage I've never heard of, in Georgia, a country I've never visited. Here was my thought process before I paid into the collection box:

"You know what? I really don't want to contribute. It's not that I've got anything against Georgia or those lovely orphans. It's just that I have no idea how my contribution is going to be used – or indeed, if it'll even make it past the border. Besides, there are other causes I actually have heard of that could use my money. And, even though it sounds selfish, I generally come to work to earn a paycheck, not give it away before I've booted up my computer."

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Nevertheless, I gave out of guilt. And I gave because I wanted to support my colleague who was doing a good thing. (I later learned that she got confirmation that 100 percent of our contributions bought the children blankets and toys, both of which were sorely lacking.)

I also gave out of spinelessness, apparently.

"The Number 1 reason Americans give is because they're asked," said Daniel Borochoff, president of the American Institute of Philanthropy.

Smart givers, Borochoff said, "have the confidence to say 'I just support the causes that I know and strongly believe in.'"

Well, for those who haven't come up with a mission statement for their charitable giving to fend off other requests, here's a news flash: You're going to have to do some research to really "know" an organization.

Consider the most compelling of the mail solicitations you've ever received. Personally, I'm most swayed by those that ask for contributions to feed the homebound elderly who don't see people much.

There certainly are some good organizations that will put your mailed contributions to good use. But then there are those who give a huge percentage of the contributions they receive to a marketing firm, in exchange for that firm taking care of the mailing, Borochoff said.

So instead of helping to feed and cheer a frail 94-year-old woman who's outlived friends and family, my contribution may end up lining the pockets of some guy who knows how to turn a profit. That's heartwarming.

Then there's the fact that no good deed goes unpunished. I asked Borochoff if there was some study that showed mail solicitations are an effective fund-raising strategy. Nope. Many charities that solicit by phone or mail, he said, "are on a fishing expedition to just get the 1 percent they can get to give again and again."

I'm certainly not suggesting we all clamp our wallets shut. But we might be more discerning in where we give and why.

After all, Borochoff noted, "there is an opportunity cost if you make a thoughtless gift. It's money taken from a cause or person that could really do something with it."

For help figuring out which charities will make the most of your hard-earned dollars, you might first check the AIP's free list of top-rated charities. If you want more in-depth information, you might purchase one of its charity rating guide reports for $3. You also might look up a nonprofit on GuideStar.org. Registering for its research reports in GuideStar Plus is free and your name will not be sold to fundraisers.

And lastly, talk to people in the know, Borochoff suggested. For instance, if animal rescue is important to you, you might ask a local zoo keeper or veterinarian which charities he or she likes.

Now if you hate the idea of researching an organization's true M.O., pick a local charity you've seen in action and give of yourself the old-fashioned way: volunteer.

Jeanne Sahadi writes about personal finance for CNN/Money. She also appears regularly on CNNfn's "Your Money," which airs weeknights at 5 p.m. ET. Please let her know what you think about this or other columns by e-mailing her at everydaymoney@cnnmoney.com.