NEW YORK (CNNMoney.com) - Some people just aren't that bright.

From tech-savvy syndicates stealing card numbers using fake ATM faces to a flawless faux-campaign raising money for the latest disaster, identity thieves are getting smarter.

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Yet some people are so careless with their personal information they are practically begging to have their identity stolen. And others don't even need to be impersonated to face financial ruin, they simply implode from within.

Don't carry around sensitive stuff

Take the person who wrote down all of the family's financial information in a day planner. As sometimes happens, the day planner was stolen. The thieves made off with names, phone numbers, credit card numbers, four bank account numbers, ATM numbers with pins, social security numbers and the maiden names of both spouses' mothers.

"All the information someone would need to steal your identity," said Jay Foley, co-director of the Identity Theft Resource Center, who helped the family resolve the issue. "Sometimes, being organized is a little too organized."

Foley said $52,000 was racked up on the credit cards in the first weekend. After those cards were maxed out the thieves took out three more. Then they took out loans for a boat and a car.

The issue was eventually resolved and their names were cleared, but it took 11 months and the resulting stress led to a divorce.

Use caution with file sharing programs

Then there are these people who think they're putting one over on the music industry by using file sharing software to download music. What they don't know is that, sometimes, they're sharing much more than MP3 files.

According to the technology blog Trenchier, it took "all of 10 minutes" to scan people's hard drives and find tax returns, bank statements, court documents, alimony papers and copies of passports using file sharing software. The people, evidently, didn't specify which files to share and which to keep private when they downloaded the file sharing software.

Clean your computer

Another problem with computers is what to do with the machine when you get a new one. One woman simply put her old computer on the curb, hard drive intact and several years of business records and personal tax forms on the Quicken program, which wasn't password protected.

"Lo and behold she was victimized, repeatedly," said Kevin Barrows, a former FBI agent who now works for Renaissance Associates, a computer forensic firm.

Barrows says when you get rid of a computer you should not only clean your hard drive, but physically destroy it. "Smash it," he said. "Do whatever you have to do to make sure someone doesn't use it."

Don't share too much information on checks

Mari Frank, an attorney and author of several books on identity theft, says most cases don't involve negligence on the part of the victim but rather result from breaches in security at a third party, such as a bank or employer who has your information.

Nonetheless, she still comes across instances that cause her jaw to drop. Such as one older man who sent her a check for a book on preventing ID theft. On the check for the book he had written his Social Security number.

"He had his identity stolen and he had no idea how this could have possibly happened," she said. "We immediately called him and said 'Look..."

Watch for scammers

Or another man who answered the phone in the middle of the night. According to Frank the caller said they were from the government and needed his Social Security number and date of birth for jury duty. The man dutifully supplied the requested information and went back to sleep. "A few months later he was victim of identity theft and he wanted to know if that had anything to do with it," she said.

Protect your pin

Tom Kelly, a spokesman for Chase said the bank will get a call from a customer who lost an ATM card and now see that money has been taken from their account.

And how is that possible without the pin number? It was written right on the card.

Watch what you spend

Some people don't even need their identity stolen to make a mess of their financial lives. One Chicago private banker got herself $325,000 in debt buying clothes so she could wear the same fashions as her well-heeled clients, according to David Leibowitz, a Chicago-area bankruptcy lawyer.

Leibowitz stressed that the vast majority of bankruptcies come from unexpected misfortunes, such as illness. But in another case, Leibowitz said a women went bankrupt under the weight of $50,000 in medical bills -- for her cat.

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