Many atimes, we usually don't notice the power of repetition and the indispensable role that it plays in our daily lives. You see, when you do something over and over again, it starts becoming a lot more easier to do and with time it becomes am automatic process where you don't feel any stress doing it.
I remember sometime ago, I was walking up the stairs of a building where I lived with a friend of mine who was visiting me for the first time. I was leading the way and in a very short time, I was at the topmost floor while my friend was still lagging behind. When he got to the topmost floor looking quite stressed, he exclaimed: "Nigel, how do you manage to climb up and down these stairs everyday?" "It's tiring", he added. I smiled, looked at him and said, "It's because I'm used to it and you're not".
It's not just in climbing stairs, repetition has strong influence over the way we think and act. If you are used to thinking negatively about your situation, it will be very difficult for you to see anything good in your life until you break that repetitive thought process in you which may have become automatic.
Repetition is also at play in the way you talk, the way you respond to people, the way you dress, how disciplined you are in your life, your career and relationship lifestyle etcetera.
To break any strong cycle of repetition, it needs a high sense of consciousness about that process. And breaking an addiction to a repetitive process like porn will need a counter repetitive process which will replace the negative one.
Getting to that point where something admirable becomes second nature to you is the goal. I call that point the 'elastic limit'. You subconsciously attain it by constant repetitive activity. It is then your whole system adapts to it and it becomes easy to always do it.
On a final note, some people like to ask the question "How long will it take?". I feel that question is for losers looking for a reason to back out or for shortcuts.
They lack that passion and dedication needed to walk the walk and that's why they want to be given a particular time when they can expect to relax and quit.