Lessons which are tagged in this way [SHAREDALL] [ASSOCIATESHARED] [SAAC03SHARED] are shared across multiple courses.

This is normal, knowledge on a given topic might be required across multiple AWS Certifications.

By tagging in this way, it allows you to choose if to skip it or not.

If this is the first course of mine you have taken ... don't skip

If you have watched a shared lesson in another of my courses but you're not 100% confident ... watch it again.

.. but if you have watched it before, and are 100% confident, skip it and save time.

It's possible to efficiently study more, in the same time, by taking advantage of shared topics.

Associate Example

Instead of 3 associate courses taking 300% of the time/effort of 1 associate course ...

by skipping shared topics .. you can do 3 courses in ~180% of the effort of 1