How can I find the total number of nights booked by a guest in a certain time period?

To see any reservations-related information for a certain period of time for a specific guest, run a Reservations report with the following filters:

 

• Mode: Totals
• Group by: Customer

 

Note: If you run this report for a longer time period, e.g. a year, it may be a very data-heavy report and it may take some time to load.