you're looking at Authorization (Not Authentication, which handles how to get the logged in user).

In Laravel, it's known as Policy. So, based on the subscribed tier, you define the borders, which area of your saas are limited to "pro", "basic", etc.

Since Laravel is an MVC, usually, you'll check this permissions in the controller. Check if user's posts is more than his plan's limit (say, 5). if he already has 5 posts, deny that request and put a nice error with message "You've reached your limit. Please upgrade your plan".

or other alternative flash the session, and redirect the users to the billing page, with a message to upgrade his plan.

What do you think?