Everything is on one task if related to the same work item. Example - the task is to organise flights for team manager:
Flights organised. Attach confirmation email here
Searched web for cheapest flights => decided on Qantas. Booked flights and paid with Visa card
I have always used Outlook tasks to manage by work. I use individual tasks to capture a running history of a work item. The body of the task will include dates as a header and then comments re the status of the work. I also drag (move) any relevant emails to the correct section ie - filed by...