You can be audited within three years after the filing deadline of your tax return or when you actually filed your tax return. However, there are two main exceptions to this rule that can extend the risk of being audited:
Every year the IRS publishes their examination statistics:
From 2008 to 2016 the overall audit rate for individual tax returns decreased from 1% to 0.7%. (For high income earners though, the audit rate has increased.)
The IRS is also auditing taxpayers with little to no taxable income. Much of this is due to the high incidence of error and fraud within the Earned Income Tax Credit.
Play It Safe
Always retain your tax records and support documents for as long as they may be needed to substantiate claims on your tax return. Make sure you consider any state record retention requirements as you review when it is safe to destroy old records. Remember some records need to be retained indefinitely. This includes, at minimum, copies of original tax returns, legal documents, and real estate transactions.