The WP database lives on the VM, so you’ll want to export the DB before destroying the VM (assuming you want to keep site content like posts, and settings like active theme, etc.). Later, if you want to continue work on the site, do a vagrant up and import your copy of the DB.
You could search the forum for ideas related to DB management, but note that for export/import you could use a tool like Sequel Pro, or WP-CLI (especially with WP-CLI aliases), or WP Migrate DB Pro, etc.
Your project files (like Sage php files) will be synced between the VM and your regular local (host) machine, so they will remain after your destroy the VM.