You can install any licence (even a single one) on any number of dev/staging sites you want.
TLDs that are considered as dev or staging:
- .dev.cc (DesktopServer)
- .myftpupload.com (GoDaddy)
- .cloudwaysapps.com (Cloudways)
- .wpsandbox.pro (WPSandbox)
- .ngrok.io (tunneling)
Subdomains that are considered as dev or staging:
- stagingN.* (SiteGround; N is an unsigned int)
- *.wpengine.com (WP Engine)
- dev-*.pantheonsite.io (Pantheon)
- test-*.pantheonsite.io (Pantheon)
- staging-*.kinsta.com (Kinsta)
- staging-*.kinsta.cloud (Kinsta)
- *.mystagingwebsite.com’ (Pressable)
Additionally, if your domain is localhost (with any port), it will also be treated as a localhost domain.