How often do you check your financial statements? The answer should be at least once a week, according to MarketWatch senior consumer reporter Kelli Grant. Checking financial accounts and statements allows consumers to catch fraudulent charges sooner rather than later and the practice helps individuals determine if they’re over budget or exceeding their smartphone data plan. The five most important accounts to examine every week are:

• credit card

• cell phone bill

• online checking account

• retirement account

• budget account software (such as Mint.com)

A 2012 study from ACI Payment Systems found that 42% of Americans were victims of credit, debit or prepaid card fraud over the past five years.

Grant says credit card companies offer the best consumer protections against fraudulent charges. Federal law stipulates that consumers are liable to pay up to $50 for fraudulent charges but the majority of credit card issuers will delete suspicious charges if flagged.

Banks offer less-friendly consumer policies. According to Grant, an individual’s liability for spurious debit card charges ranges from $50 (if the problem is reported within two business days) to $500 (two to 60 business days). Consumers are on the hook for all fraudulent charges if no documentation has been filed after 60 days.

Americans may also need more protection from their own banking mistakes. A Center for Responsible lending study determined that Americans age 18 to 24 pay nearly $1.3 billion in overdraft fees every year compared to $6.2 billion for individuals aged 55 and older. The typical overdraft is $20, which triggers an average fee of $34, Grant notes.

Monitoring one’s cellphone or smartphone bill online can prevent costly text, talk and data charges. Most wireless carriers will send free text alerts to users if they’re close to hitting their cellular plan ahead of schedule. But it’s very easy to lose track of minutes and texts, Grant says. Verizon Wireless, for example, charges its customers $0.45 for every text message that exceeds the users’ monthly plan. Moreover, the company bills users an extra $15 per 1GD of data used if they're over their Share Everything Data 2GB ($60) plan, according to Grant.

Finally, individuals should track their weekly expenditures on budget accounting Web sites like Mint.com to get a complete picture of where and how they’re spending that hard-earned cash. These online sites allow users to review their balances and transactions for all accounts – credit cards and retirement accounts included – usually at no extra cost.

Grant says it’s a good idea for consumers to look over their spending habits every few days to see if adjustments need to be made (and to prevent an extravagant shopping spree that may be regretted later).