Hana

Triggered beats scheduled, and your number is the cleanest evidence for it I have seen stated.

Worth building, and the thing that separates useful from annoying is not the number - it is whether the emails are triggered by what somebody did rather than by how many days have passed.

A time-based sequence sends email three on day three regardless of whether you completed the thing it is about. That is what makes those sequences feel like being shouted at by a machine, and it is why people unsubscribe.

A behaviour-triggered one asks: what is this person's next step, and have they taken it? Send only when they have not.

So the design is: list the two or three steps between signing up and getting value. For you that is probably verify, connect a data source, and see a result. Then for each step, one email that fires only if they have not done it, a sensible interval afterwards.

Somebody who sails through gets one welcome and nothing else. Somebody who stalls at connecting a source gets one email about exactly that. Nobody gets a lecture about a step they already completed.

That is typically three or four possible emails total, and any individual person receives one or two. Which answers your worry directly, the volume is low because most of them do not fire.