A few points to remember
As of the Winter'17 release, Enterprise Territory Management is available in Salesforce Classic only.
Each territory can have up to 15 assignment rules.
Only one model can be in the Active state at one time in your organization.
If you disable Enterprise Territory Management, your users will lose the record access that was based on territory assignment.
By default, each territory model can have up to 1,000 territories.
As of Winter'17 release, Enterprise Territory Management components cannot be included in packages or change sets.
