What is average meeting prep time per person?

Very little, indeed because of GTD. But people do review their projects often shortly before the meeting, which costs you 5 minutes. Also, most roles report on metrics and they have to make sure they’re filled in correctly. Most are done automagically (from Google Analytics, Mixpanel, our own API) but some have to be entered manually. That takes another 2 minutes per metric, max 15min in total.