Warrillow sorts subscription businesses into nine models, and the one that interested me is monitoring: someone watches something on your behalf every month and tells you when it changes. Not support, not banked hours — an alert with judgement behind it.
What I did with it
The Odoo upgrade radar made sense as a one-off: here is what breaks if you move up a version. Warrillow made me see that the value does not expire the day I hand over the report, because third-party modules keep changing every week. Monthly monitoring came out of that, with the year paid up front as an option.
He also left me the numbers I was not tracking: how much revenue recurs, how many customers cancel, what it costs to win a new one without counting people I already know. And a threshold: if a customer is not worth at least three times what it cost to acquire them, the model does not hold however good it sounds.
One decision of my own, not from the book: do not switch the subscription on until a handful of people have bought the one-off report. Selling a monthly promise before having delivered the one-time version is the fastest way to disappoint someone for twelve months straight.
What I left out
The company-valuation chapters. Much of the book is written for someone preparing to sell their business at a higher multiple, which is not my situation.