SaaS METRIC OF THE WEEK: Renewal rate
You have to scroll down to the bottom of this articlebefore you get to the informative bit on measuring this metric, but don't! (I could link you to this one). Please read the first part, too - it's great. TL;DR: Don't be a jerk when it comes to renewals. If you have to be, maybe it's you, not your customers (and then keep scrolling again to see the 5 main reasons why people unsubscribe). This additional article fromProfitwell on Renewal Rates also describes the differences between retention and renewals.