[patio11]

Dharmesh Shah has talked about it extensively -- basically, of people on monthly billing, at any given time approximately 100% are at risk of churn. Of people on annual billing, < 10% are at risk of churn at any given time. They also have less opportunities to hit involuntary churn like, e.g., getting a CC declined or expired.

[dshah]

Indeed, that's true.

One additional point: Customers that commit to annual billing generally tend to churn less often overall -- because they've made a more "considered" purchase and committed more time to the purchasing decision.