An IRS audit does not automatically mean fraud, penalties, or a worst-case outcome. In many cases, it starts with a records request, a mismatch, or questions about a deduction, credit, or income item. Still, the way a taxpayer responds can shape whether the matter stays narrow or expands into something more expensive.
The IRS says it closed 505,514 tax return audits in FY 2024, with $29 billion in recommended additional tax. That number alone helps explain why seemingly small response decisions can carry real financial consequences during an examination. IRS Statistics of Income
In this post, you’ll learn seven common audit mistakes that can increase tax exposure, why they matter, and what taxpayers often consider when trying to keep an examination from getting broader, slower, or harder to resolve. If you want a broader overview of the process first, this guide to how IRS exams, records requests, and proposed changes usually unfold gives useful background before diving into the pitfalls.
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An audit is often about substantiation. The IRS generally examines whether income, expenses, and credits were reported accurately, and it uses document requests to develop the facts. In IRS guidance, the primary method for obtaining information during an examination is the Information Document Request, or IDR. IRS Internal Revenue Manual IRS Publication 3498
That matters because tax exposure often grows in layers:
Here’s what this often means in practical terms: the audit risk is not only about the original line item. It can also be about how the file looks once the IRS compares the return, the supporting records, and the taxpayer’s responses over time. IRS Publication 3498-A
One of the most common mistakes is treating the first IRS notice like ordinary mail and setting it aside. Many audits begin by mail, and the initial letter usually explains what issue is being reviewed, what documents are requested, and when the response is due. The IRS’s audit publications describe the process as: review the notice, gather and compare information, and reply by the stated deadline. IRS Publication 3498-A
When that first deadline passes, several things may follow:
The IRS also notes in its audit reconsideration materials that many taxpayers later seek reconsideration because they did not appear for the original audit or moved and did not receive correspondence. IRS Audit Reconsideration Process IRS Publication 3598