Multi-tenancy can be applied in various scenarios, one that comes to mind is the medical field where the data of one clinic should not be accessible to another. Multi-tenancy allows you to maintain a single code base and a single application without the need to duplicate, and thus multiply, the costs of maintenance and server resources. Depending on the criticality of the data, you can choose one of three approaches. Personally, I recommend the schema-based approach, as I believe, in my opinion, that it strikes the best balance between efficiency, cost, and security.