Book the follow-up hour before doors open
The follow-up dies in the gap between "we should send something" and actually sending it. Close the gap in advance: put a one-hour block in the calendar for the morning after, with a name next to it.
Within 48 hours, the event is still a story people are telling. By day five it is competing with everything else in their week, and a thank-you reads like an afterthought.
For a multi-day conference, start the clock when it closes, not when it opens. People need a day to get home and dig out of their inbox.



