"The tax auditor will usually spend three to four days on an average small business file where the job involves two taxation years. That is general. However, the auditor could spend as little as a day or as long as several weeks. The longer they spend, the harder they will look for things to justify the audit to the supervisor. That is human nature. For that reason you want to pin down the exact taxation years and have complete records available for those years."
Irving Rosen, senior tax advisor for the Canadian Federation of Independent Business