The toothbrush test isn't just retention, it's also about sales velocity. A product used monthly tends to have a slower sales velocity than a product used weekl

The toothbrush test isn't just retention, it's also about sales velocity. A product used monthly tends to have a slower sales velocity than a product used weekly. The pace of the decision cycle is related to frequency of use. For a monthly use product, the moment the customer learns about the product will be an average of 2 weeks from when she needs it. That's two weeks for her mind to get distracted with other things. It's easy for the evaluation to get pushed by one or more intervals, and even once the decision to purchase has been made, there might be a month delay before the close and that's a month in which urgency can fade and a chance for it to get set aside. Note how sales velocity and retention are similar, can you retain customer interest long enough to close a sale? There are successful occasional use products. It's not meant as a threshold or black and white test, its just one factor to consider when choosing which business to start.