I use this 1-2 days per week with more focus in the winter for over 1 year. I recall when level 2 and 3 were hard and 4 was impossible. Now I do 2 and 3 regularly. They are my favorite. Level 1 is now too easy. Level 4 is ok, but not my fav. My arms are really lean because of this tape. Thank you Jollian and team for the variety.