I´m not sure whether you´re a bot or not, insisting on spreading negativity on your every comment. And there are many. To any humans reading this: Please don´t let moron bots like this stop you from believing in the goodness of humanity.

totally depends on what your ultimate goal is.

independent from that, i recommend the highly customizable exercises at musictheory.net - knowing how stuff works is good, practicing it until you recognize it instantly in sheet music and/or on the keyboard is a whole other beast.