So where did I get my four year idea from? The IRS generally has three years from the date you filed a return to initiate an audit. Some states have a longer period of time, for example California has four years to audit a taxpayer. But I have seen instances where the IRS or a state tax agency requests a tax return from a much earlier year, often when the agency has never received an original return. And older documents have a way of being purged after three or four years, and so digging up older documents is often an arduous process. As a result, I'm now inclined to agree with Vohwinkle about keeping documents for a longer period of time.