What is meant by small, small, large PHP project?

Question

PHP

I often come across expressions like "The solution is suitable for small projects, but for large ones you need to use ...".
Question: on the basis of what criteria is such a division made?
Please provide examples of small and large projects.
Interested in CMS, CRM systems, etc.
PS. I understand that a business card site is a small project, and google is a large one. No need to write about them ;).

Answer 1

It depends on the number of technologies that will have to be used to implement it.
Now I will conditionally set myself tasks for the development of projects of 4 levels of complexity.
Technology:
What's this Google? Nothing. It's over the top in complexity.