Can I delete all tickets older than X days?

You need to create a filter of the tickets that were created from when you started using Freshdesk till the date you want deleted. You will have to choose a custom date range in the 'Created' field. You can delete the tickets in bulk (30 at a time) However, if there are tickets that have been archived (tickets closed for more than 120 days) which you can view from the ticket list view page--> Click on the view name at the top--> Go to the Archived folder--> These cannot be deleted or none of the properties can be changed. However, since we adhere to GDPR if you permanently delete a contact from Freshdesk, all his tickets (Including the archived ones) will be deleted.