Not doing any learning for 2 weeks sets you back a lot. I had finished 30 lessons, and now I have to do the last week's lessons all over again. I really need to be consistent, I'm never going to learn if I keep having to backtrack like this.

Persistence is the key and a good quality . Because that quality makes people to achieve their long term goals without any motivation. Without that quality, you wouldn't become a successful person that easily.