Not every event is a trigger. A trigger is a usage pattern that reliably precedes a customer being glad you reached out. Build your library from the highest-hit-rate signals first, then earn the right to subtler ones. Four families do most of the work, and in practice the top three behavioural triggers drive roughly two-thirds of all automatic expansion conversions, so the library does not need to be long, it needs to be sharp.
Capacity triggers are the bluntest and the best. A team crossing roughly 80 to 90% of its seat allocation, or 90% of its allotted API calls or storage, is the canonical expansion signal, because the customer is about to feel the ceiling whether you call or not. A common, well-worn rule fires when an account reaches three-plus seats or 90% of quota, whichever comes first. These convert because the offer relieves a pain the customer is already living, which is why product-qualified accounts crossing a usage threshold convert at 25 to 30% against a traditional marketing-qualified lead nearer 5 to 10%.
Adoption-spread triggers catch the land-and-expand motion in flight. When usage jumps from one department to three, or when week-over-week seat growth runs hotter than the account's own baseline, an expansion conversation should open automatically, before the champion has to fight for budget cold. Week-over-week usage growth is among the strongest leading indicators of an account deepening rather than drifting.
Feature-edge triggers are the cleanest cross-sell. When a power user requests, or repeatedly bumps into, a capability that lives in your enterprise tier or an adjacent product, that is the customer telling you the next SKU by their behaviour. No survey required; the usage is the request.
Value-milestone triggers govern timing. The right moment to expand is after the customer has achieved measurable value, never before, because the only durable expansion pitch is an evidence-based case that more investment amplifies value they can already see. Accounts that hit their activation milestones inside the first 90 days cut first-year churn sharply, so milestone completion is both a health signal and an expansion trigger; the activation-rate is the gate every other trigger sits behind.
The discipline that separates this from spam: a single threshold crossing is a candidate, not a command. The 90%-seats account that also completed an activation milestone and spread to a second team is a different animal from the one that briefly spiked because somebody bulk-imported users. Define each trigger as a named, testable condition over real product data, the same way you would assert a value, never a vibe. The companion spoke on building expansion signals into your motion goes deeper on instrumenting the streams themselves.