Originally Posted by: frankht
I looked at the lessons you linked below and I noticed that some of them are not part of a particular course.[/quote]
There are three categories of lessons on the site.

1. Course lessons (GF1&2, Blues, Rock, Country)
2. Songs
3. Catalog

Essentially, everything that doesn't fit into a course or a song is in the catalog category. You can find a list of of all the tutorials, including the catalog material here:

http://www.guitartricks.com/tutorials.php
[QUOTE=frankht]
... how do we know when to incorporate them into our studies?

This is a great question. :)

The search function on the site works pretty well, and the page with all the tutorials shows everything available. But that assumes you already know what you are looking for. And if you are a student, that is obviously not always the case.

For now the best thing to do is simply ask an instructor where to find something once you have some specific skill, knowledge or goal in mind to learn. For example, the lessons I linked are related to a list of mine that broadly deal with Learning To Play Lead Guitar.

Hope that helps. Best of success!