Drupal is an open source framework, but a strategy should be taken in place in order to plan how to use it at the best of its capability and performance.
The fact that the Drupal is written in PHP means that each module is loaded for each page load, therefore is highly recommended to install a module only if it is really necessary. My advice is to plan and make a strategy, basically make a list of all the modules that can be used in the project.
Drupal 8 Architecture is very robust, fast and Object Oriented. The Drupal Core rely on many Symfony base Components that give a great entity abstraction.
Plan your content types, permissions, roles, views and taxonomies. Set up different contexts, view modes, panel variants and view.
Do you need a very simple marketing brochure website or a very big robust intranet system? Plan which modules you need to install and keep it simple!
Migrate Drupal by follow our very simple Six Steps! Set up your YML configuration to define your custom migrate modules to import data from Drupal 7.