How long a content audit will take depends on how much content you have and how many criteria you choose. It’ll probably take you a day or two to get an inventory together and set your criteria. For the audit itself, as a rule of thumb, expect to be able to audit an average of six pages per hour. So to audit everything on of a 100-page website might take two or three days. You’ll probably want to spread that out over a week or two though, as auditing can be hard work. If you have a big site, a content audit will expand to fit the time available, so it’s really up to you to decide how much time you want to spend on it. Rather than auditing every page, choose a smart, representative sample of content.