What is the difference between cloning last year's event and reusing last year's event? How do I know which to choose?
When you clone an event, all the information from your previous event such as orders, participants, and website pages are stored in your system separately as an Inactive event (from Events -> Overview -> Inactive Events). By going here and clicking on the event in question, this allows you to access the data for reference purposes. This is the most common method for restarting your event.
If you are reusing last year's event, you will simply work over top of your old data. When you renew, all orders and participants from last year's event will need to be cleared before restarting your registration process. When this is done, data from the previous event will no longer be accessible.
These processes are outlined further at: Restarting from last year's event