The Perennus Letter

Where lifecycle revenue goes missing.

Findings from Perennus research and the Studio: how products keep, lose and win back their customers, with the method shown and the limits of the evidence stated.

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Recent editionsThe Perennus Letter

The Perennus Letter 4 Aug 2026 The Moment Your Customer Starts Reconsidering Why high-retention systems remove decisions before they create churn. (opens in a new tab)
The Perennus Letter 28 Jul 2026 Your Customer Cancels Long Before They Click “Cancel.” Why healthy retention systems monitor changing behavior, not disappearing users. (opens in a new tab)
The Perennus Letter 14 Jul 2026 Your ESP Says “Delivered.” Gmail Disagrees The deliverability metric that quietly convinces growth teams everything is fine. (opens in a new tab)
The Perennus Letter 7 Jul 2026 Your onboarding emails are running on a calendar. Your users aren’t. Why treating every user the same is quietly hurting activation and retention. (opens in a new tab)

What you get

Three kinds of edition.

Research
Teardowns
Products taken apart in public: what we noticed, how we checked it, and where the evidence stops.
Patterns
How lifecycle systems work
The mechanics behind activation, retention and win-back: triggers, timing, segmentation and ownership.
Studio
Notes from the work
What client lifecycles reveal, anonymised, with the evidence behind every claim stated.

Themes

What the Letter covers.

ActivationWhether new users reach the moment the product proves its value, and what stops them.
Silent churnHow customers disengage long before they cancel, and what notices.
DeliverabilityWhen “delivered” doesn’t mean arrived.
Ownership and dataWhich system owns which customer relationship, and what it knows.
EvidenceWhat can be measured, what is inferred, and what should be left unstated.