I have been asked this question countless times.  There is a ten year statute of limitations on collection of taxes.  This means the IRS has ten years to collect taxes from the time the tax return is filed and assessed, not from when it is due.  Thus, if you filed your 2002 taxes in 2011, the ten years would not be up yet.  Also, there are several events that can extend the statute, such as filing an Offer In Compromise or filing bankruptcy.  In addition, many of my clients have entered into an Installment Agreement before coming to me and have signed a waiver extending the statute without realizing it.  After the statute expires, the remaining unpaid taxes are written off.  I can determine when the statute began to run for each year that my client owes taxes and when it will expire.  Then I can determine the best method to use to save my client the most money.  Remember that if you do nothing, this will lead to levies against your wages and/or bank accounts.