[al_f]

I struggled with waiting fors as well initially. The workflow I've settled on now is entering a waiting for in a project after each delegation step, so the waiting for automatically becomes active once the delegation action is done e.g.

Email Bill to ask for copy of proposal (computer)
Bill - copy of proposal (waiting for)

I look at the waiting fors in my reviews (usually weekly but more often if I've got a few time-critical things on the go) and fire off quick less-than-2-minute reminder emails if anything is taking longer than it should, thus avoiding the need to enter new email actions for the reminders.