Most Mystery Consumer Providers will assign work based on your availability. Thus, if you want to work more, you will be assigned more work. On average a company will ask you to work a certain number of hours each month to ensure your continued employment. This varies depending on the provider but is usually about 20 hours a month. If you have more time to dedicate to shopping you can work as much as 20 hours a week and even closer to full time hours depending on the relationship with your provider. A full time shopping job is considered closer to 30 hours a week because of evaluations and preparation time involved. Again, full time Mystery shopping jobs are harder to procure and while some shoppers work full time it is rare that they would work 40/hrs a week consistently.
The better your relationship with your provider, the more likely you are to procure assignments. Additionally, providers represent the best way in which to receive consistent work mystery shopping; this as opposed to independent shoppers who are responsible for finding their own work.