The whole point of taxes is to raise money to help pay for programs and services authorized by state and federal governments. Here are some examples of what your federal and state income taxes help to provide. Federal taxes help pay for: National defense – Securing America and protecting its interests overseas. If you file your taxes but don't pay them, the IRS will charge you a failure-to-pay penalty. The penalty is far less: Generally, the IRS will charge you 0.5 percent of your unpaid taxes for each month you don't pay, up to 25 percent. Interest also accrues on your unpaid taxes.