Why this decision matters
CRA contact spans a wide spectrum, and knowing where a letter sits on it removes most of the fear. At one end: pre- and post-assessment processing reviews — automated requests to substantiate a specific claim, resolved by sending the documents. In the middle: desk reviews of a category, such as vehicle expenses or GST/HST input tax credits. At the far end: a full audit, where an auditor examines books, records, and bank deposits across one or more years.
Across the whole spectrum, the same asset decides the outcome: records that exist, reconcile, and can be produced on request.
The central idea
An audit is won years earlier, in the bookkeeping. The response window is merely where that preparation is revealed.
The standing preparation is unglamorous and decisive: six years of retained records (the statutory requirement), receipts attached to transactions in your accounting file, bank and credit accounts reconciled monthly, a vehicle log that actually exists, and personal and business finances that never mingle — because in a full audit, unexplained personal bank deposits are the classic route to an assessment of unreported income. Businesses whose books close monthly walk into reviews with their evidence already organized.
When the letter arrives: read precisely what is asked, respond by the deadline (or request an extension before it passes), send exactly what is requested — complete, organized, and nothing gratuitous — and keep copies of all correspondence. For anything beyond a simple receipt request, involve your accountant immediately and authorize them to deal with CRA directly; answers given casually in early conversations frame everything after. If the outcome is wrong on the facts or the law, the appeal path is formal and time-limited: a Notice of Objection, generally within 90 days of the assessment. Cooperation and organization shorten reviews; missing records and improvisation extend them.
Educational use notice
This publication is part of the Numera Decision Library and is provided for education only. It is general information — not accounting, tax, legal, or investment advice — and it does not consider your personal circumstances. Every guide is grounded in official guidance from government and regulated authorities — including the Canada Revenue Agency (CRA), the Department of Finance Canada, Service Canada and Employment and Social Development Canada, the Internal Revenue Service (IRS), and the Canadian Centre for Cyber Security — with the sources listed at the end of each guide. Tax rules and dollar limits change; confirm current figures with the official source, and speak with a qualified professional before acting on any decision discussed here.
Official references
Sources are official government and regulated-authority publications. Official sites reorganize periodically — search the document title if a link has moved.