We can waist lots of time, doing the same things over and over again in meditation, if we don't sometimes pull back and look at what we are doing.

There are many hindrances (nīvarana) in meditation, and if you are not aware of these, or do not understand them, you can waste a lot of time. Podcast episode can be found in the article.

Jhana has become popular, but often dumbed down. So then it helps to have an overview of how aspects of the path fits together.