As far as I am aware this is how it works with all addictions. So mainly things like alcohol, drugs, PMO, in other words super normal stimulus's. But once you have become addicted to these things through years of continued use, even if you stop using these things for long enough the pathways never 100% heal. It can heal to the point urges can potentially fade to near non existent, your behaviour changes, and you stop seeking and using. But the pathways always lay dormant, and can be heavily activated again. So an alcoholic who has been on the wagon for years walking in to a bar, smelling alcohol, these things could send his previously addicted pathways in to a frenzy, causing the alcoholic to get a powerful urge to use. The same goes for a PMO addict who has not used in a long time. Accidentally seeing something online could send their previously addicted pathways in to a frenzy, causing them to get a powerful urge to use. Basically these pathways never 100% heal. It seems to be worse if you have become addicted to a super normal stimulus in your adolescent years, as this is when your brain is at it's highest in neuroplasticty. Basically this is when your brain is really learning what it is supposed to do in life. But even if you have become addicted to something after your adolescent years, it can still be a big problem. But it just seems to be worse if you become addicted in your adolescent years. Sexual urges and sex are probably our most powerful natural craving and reward. Sexual urges will never go away completely for the majority of us. Having a sexual urge could be a trigger to PMO, and like I said sexual urges are still going to be there, even after you have 100% rebooted. Another issue is porn and artificial sexual stimulation is everywhere, accessible in seconds on your smartphone, computer ext. Guys who have never been addicted to PMO, who have never developed any sexual dysfunctions from it still occasionally like to use PMO. So how difficult is it going to be for guys who have previously been addicted to never use it again? Another thing is what if a guy has 100% rebooted but he's not getting any female attention? Even something like that could lead the guy back to PMO, because if he's not getting any female attention for long enough he is eventually going to look elsewhere, and we all have access to unlimited sexual stimulation in one click. Something that kind of annoys me about a lot of guys on this is they think it's abnormal to be turned on by porn. They also think once they have 100% rebooted they will no longer be turned on by porn. The behaviour might change, but porn will always have the potential to be arousing. You weren't addicted to porn the first time you seen it and it likely turned you on? Guys who don't have an issue with PMO can still find porn arousing and appealing. Look at it this way, some guys will say it's abnormal to enjoy watching attractive women on a screen, it's abnormal to be aroused by that. But do you not watch movies and tv programs on a screen? It must be abnormal to enjoy them, it must be abnormal to enjoy watching anything on a screen, because it's on a screen and not in real life. It's a bit ludicrous. All I'm saying is it's not actually abnormal to be aroused by hot women on a screen, and even if you have 100% rebooted you probably could still find hot women on a screen arousing. But it's even worse for a PMO addict who hasn't used for a long time seeing things like that, because like I said old pathways could heavily light up causing a powerful urge to use, and if they do use then old behaviours could rapidly return.