This will depend on the time you have available, the way your work is organised, and the pace of research in your group’s area.
It is advisable to run searches in CENTRAL every month to capture new records.
For MEDLINE or other databases, automated alerts can be set up so the database is automatically searched using your saved scope search strategy (e.g. once-a-week or once-a-month) and the results are emailed to you.
The more frequently you run the searches, the more manageable the number of records you retrieve and need to screen should be.