Let me tell you the magic that a strong purpose can produce.I was addicted to pornography for about 4 years.And in the 3rd year I was depressed all the time , because porn consumed most of my time and I was not able to achieve my goals. I tried Nofap during that time and i would'nt be able to maintain a bare streak of a week. But as the year progressed,My sexual tastes became more and more socially repugnant and even crazy.In the 4th year(i.e now)I started fapping to videos of cuckoldry, this scared the shit out of me. Then I watched a video of a Nofap youtuber called "mattWhatitis",he made a video on weird fetishes and sexual conditioning.He said that the things which arouse a teenager(which i happen to be)can start becoming the only things that arouse him in the future.In my case that could be cuckoldry.This terrified me, more than anything else ever before.He then continued by saying, abstaining from porn for a while can bring sexual tastes to normal. So getting my sexual tastes back to normal especially away from cuckoldry became my soul-motivation, and gave me a strong purpose to stay away from porn.Then, for the first time in 4 years, I stayed away from porn ,for about 2 week.It's not a lot ,but the thing which motivated me to do so ,surely played its trick. So, if you want to complete the 90 day challenge,it makes sense to say that , A strong purpose will give success.The purpose can be anything but it needs to ignite that flame in you.