I believe this has been answered here before but I can't find the question.
The article is right, when you want to rebuild your index with ALL of your content you will run a Full Crawl. An Incremental will add any new items to your index, running this may depend on how often you add content. Running a Full Crawl is good once a week as it then sets your index with all the content in your repositories, and will also be sure to remove older content that no longer exists. While this does happen on Incremental Crawls when content is moved or deleted it is supposed to be removed within the next 72 hours often I have seen this happen more successfully on Full Crawls.
Running the Full Crawl on your content to reset your index is a better mechanism that trying to drop and recreate it on demand, which if done often enough can cause problems.
You can get more on the same questions asked on MSDN