Hello, for me it depends on the item.
If it's something requiring an action, then the day before or even first thing on the morning it's due, I convert it to a task, due for that day. This way it's on my NA list and can be ticked off as completed etc.
I did create a macro to do this automatically - the macro would go through a given days all day events and ask me if I wanted to convert them individually to tasks etc but after a recent re-install i've just been right clicking and dragging them to the tasks icon.
Converting them to a task also makes it easier not to lose them if they're not completed on that day. They'll be in the NA list as overdue tasks rather than dissapearing off the calendar as a past all day event.
If it's non-actionable or is something that "actions itself" (such as a bill being paid by direct debit or standing order) then I'll edit the subject and put Done or Paid etc in there too.
Hope this helps!
Andy D.