Every taxpayer is entitled to a standard deduction.  For 2009 it will be $5,700 for individuals and $11,400 for married filing joint taxpayers.  In general, you will claim the standard deduction if it is more than the total of your itemized deductions.  Itemized deductions most commonly include sales tax, property tax, mortgage interest, and charitable contributions.  If you are single, and your itemized deductions equal more than $5,700, then you will want to itemize your deductions instead of claiming the standard deduction.  One variation to keep in mind for this year is if you pay property taxes, you can opt to increase your standard deduction by the amount paid or $500 ($1,000 for joint filers), whichever is less, so you may want to pay your 2009 property taxes before year end.  A tax professional can help you determine the best approach.