The Dodd-Frank Wall Street Reform and Consumer Protection Act allows retailers and other merchants to set a minimum purchase amount for credit card transactions. “The minimum purchase amount must not exceed $10 and does not apply to transactions made with a debit card,” Visa explains on its website.  Before the new Act went into effect, some merchants imposed credit card minimums on customers in violation of card network rules. Vendors can now set a $10 credit card minimum without penalty.  Avoid this restriction by carrying at least $10 or a debit card in your wallet.
Under the Credit Card Accountability, Responsibility and Disclosure Act of 2009, or Credit CARD Act, if you’re under 21 years of age, you must have either sufficient income or assets, or a co-signer to get a credit card. Issuers aren’t required to offer a co-signer option, however.
Before submitting an application, check with the card issuer to find out what the policy and procedure is regarding applicants under the age of 21. 

Save the credit card agreement summary – In addition to the credit card agreement itself, new cardholders must receive a one-page agreement summary, as required by Federal Reserve regulations that took effect July 2010. This summary should highlight the key terms of your contract. File it away for future reference.

Watch for changes to your existing credit accounts.

Under the CARD Act, issuers must provide notice of certain changes to accounts 45 days before they take effect. For instance, issuers must give 45 days’ advance notice before increasing the required minimum payment. The law doesn’t require advance notice of all changes, however. Changes that don’t have to be announced ahead of time include credit limit reductions and account closures.

Certain changes you can opt out of, such as increases to fees that were disclosed in the account-opening table. To allow for response time to an undesired change, open mail from card issuers immediately.

Use the credit cards you do not want to lose.  Though the Credit CARD Act banned issuers from charging inactivity fees, nothing prevents an issuer from shutting down an unprofitable account or reducing the credit limit. As our 2010 study of credit card fees shows, a number of card issuers close accounts if they go unused for too long.While there are no guaranteed ways of preventing an unwanted shutdown, it’s smart to regularly use credit cards you want to keep. Pay in full to stay out of debt.