Yep! I find many tutorials to be great at explaining how to accomplish a simple task, but not so great at explaining how it's actually done under the hood. A true understanding of how it all really works goes a long way in making sure your designs will handle corner cases or unique configurations.
I tend to reinvent the wheel a lot as a way of quizzing my own understanding. Writing my own AVR C modules for these things quickly points out the areas I don't know as well as I think I do. Then, it's back to data sheets and blog posts I go. I'm happy to be able to pass on the knowledge that I've collected from so many other incredibly valuable sources along the way.