• The Customer-Base AuditPeter Fader, Bruce Hardie and Michael Ross, 2022How to read your own customer data: cohorts, survival and the reports that lie. The best companion to part two.
• SubscribedTien Tzuo with Gabe Weisert, 2018The case for the subscription model from the founder of a billing company. Read it for the ambition, and read parts three and four of this guide for the fine print.
• The Automatic CustomerJohn Warrillow, 2015A practical survey of subscription models beyond boxes, useful for deciding which kind you’re building.
• The Membership EconomyRobbie Kellman Baxter, 2015On memberships as relationships rather than billing arrangements, and what members expect in return.
• Trustworthy Online Controlled ExperimentsRon Kohavi, Diane Tang and Ya Xu, 2020How to run the holdouts this guide keeps asking for, and how to believe their results.

And the research: DellaVigna and Malmendier (2006) on paying not to go to the gym; Einav, Klopack and Mahoney (2025) on inertia and card replacement; Miller, Sahni and Strulov-Shlain (working paper, 2026) on auto-renewal defaults; Lewis (2006) on acquisition discounts; Datta, Foubert and Van Heerde (2015) on free-trial customers; Kivetz, Urminsky and Zheng (2006) and Nunes and Drèze (2006) on progress toward a goal; Ascarza, Iyengar and Schleicher (2016) and Ascarza (2018) on retention offers; Iyengar, Park and Yu (2022) on paid membership. Full references are in Appendix C.