In the HERE platform, the base URLs for a REST API are unique for each catalog and may differ between catalogs. For example, the base URL for the Blob API of a catalog can have a different base URL than the Blob API for another catalog. Use the API Lookup service to get the actual base URLs for the Data API.
Once you have the base URLs for a specific catalog, you can cache them according to Cache-Control HTTP Header, typically for an hour. There is no need to perform an API lookup request each time you make a request to a Data API.