>> A rough advance estimate of retention is the "toothbrush test": do people use it as often as a toothbrush That fails to capture the power of recurring servi

>> A rough advance estimate of retention is the "toothbrush test": do people use it as often as a toothbrush That fails to capture the power of recurring services. If a user needs to think of your service then sure, it needs to be a toothbrush. When the customer schedules your service, enjoys the benefits and pays without thinking about it you don't need to be a toothbrush (a lot of the SaaS world). Then there's the insane profits between those two models like TurboTax. The toothbrush analogy is a nice way to categorize certain businesses, but it's only one of many profitable consumer software models.