My personal feeling - as long as you are prepared to do a lot of the work manually the payroll module is not necessary until you have four or five active employees. You will have to use something like PDOC on the CRA website, monitor deductions for compliance, prepare T4 forms at end of year, and be able to  complete an ROE when necessary. These are the big things that the payroll module, when set up properly, does for you with only a few clicks of the mouse including the CRA filing right from Sage 50.