The IRS is able to audit your tax return for three years after you file it and  you are able to amend a tax return for three years after it is due. So you should keep at least 3 years of tax forms and tax documents, showing all your income, expenses and deductions for that amount of time. This year, you will want to have tax files for 2014, 2013, and 2012. Obamacare has also added the need to keep track of health insurance records along with your tax documents starting this tax season.