Pen and paper - I use a light colored construction paper (different color for each month) and a sharpie. For me it helps add emphasis to my good and bad decisions when I have to write it out.
I also write the "6 month plan" and the "1 month plan" on each month, so I can see where I'm at.
I found that the "I don't budget but I live comfortably" years involved a lot of waste. That lead to bad habits. Once I started better tracking, I found that I could spend considerably less on dining out and Christmas presents and my life wasn't any worse or less comfortable. Being ahead of schedule became the new "being on schedule". It was a bit stressful at first.
My girlfriend uses excel. She has more natural great habits in terms of finances than I do.
Donny: Are they gonna hurt us, Walter?
Walter: No, Donny. These men are cowards.