In these tough economic times, more and more Americans are putting their purchases on plastic. But beware, most credit card companies are now reducing their customers' credit lines, which can harm your credit rating.\r\n\r\nSan Diego resident Rakel Marquez says she's cracking down on how much she uses her credit card.\r\n\r\n"Nowadays people use their credit cards for everything, and before you know it, it's over the limit," Marquez said.\r\n\r\nAnd that credit limit may be lower than you think. In the midst of the current credit crunch, 62 percent of credit card companies have cut back the lines of credit available to their customers, and those lower limits can have a big impact on their credit scores and interest rates. \r\n\r\nSheryl Bilbrey of San Diego's Better Business Bureau says it's crucial to read any correspondence your credit card company sends you.\r\n\r\n"You need to read what you're receiving and understand what terms may be changing in your arrangement with that financial institution, because we're seeing some pretty significant changes," Bilbrey said.\r\n\r\n"I have a tendency to think it's junk mail and throw it out," consumer Sara Ledgerwood said.\r\n\r\nA slashed line of credit not only means less buying power, it also places you at a greater risk of exceeding your limit, and being hit with a hefty late fee and hiked annual percentage rate. A lower limit also means consumers are using up a larger percentage of their available credit, and that can lead to a lower credit score. \r\n\r\nTo protect yourself, consumer experts advise keeping your credit card balance below 50 percent of your credit limit. Thirty percent is even better. Always pay your credit card bill on time - even one day late now can potentially damage your credit score. And negotiate with your credit card company to push for better rates and higher limits, even threatening to take your business elsewhere, if that's an option, to get the best deal.\r\n\r\n"You could decide to go with a different lender, and that may be a good choice for you at this time," Bilbrey said.\r\n\r\n