You are hitting on something wide-ranging that many folks get all caught-up in, so this is gonna be a megillah. First, I need to remind you that I do not speak for GYE. Guard does. I am sober today b'chasdei Hashem through SA, and I do as they do, even today. GYE serves a wide range of yidden. Many are addicts, but many are not. As an addict in 12-step recovery, I firmly maintain that no one is able to tell anyone else if they are an addict or not: the entire meaning of the 1st step is that a person comes to that conclusion themselves, without any outside assistance. That is the only way they know it's really the truth and that they will never be able to run from it. If the facts are to make any difference at all for change in living, they need to really be known by the person. That only happens in the heart (which is also why "Rachmono liba bo'I"). Thankfully, GYE leaves the truth about us, up to us.
Surely there are many sweet yidden who are occasionally nichshol in terrible aveiros for whatever reason, but consider it a rare occurrence. They see they need help to keep their avodah clean. Perhaps they have never even been nichshol, but fear they may soon be. They need to find a place where they can let the truth out and get advice to protect themselves from the mess out there, and perhaps even from the mess inside them. GYE has tools, friendships and chizuk to help many. Some may thereby gain the freedom to choose to open up to their Rabbeim, wives, safe friends, or to a professional about their struggles and fears and get help that way. Some may get the strength and clarity they need to successfully stay away from the fire of lust and temptation, and remain clean and happy - just by opening up!
Some members of GYE consider their main problem that they are doing specific aveiros. Many of those are looking at schmutz, fantasizing, and masturbating; others are doing other embarrassing behaviors, others are using women (or men); some are single and others are married. They see their problem as encapsulated, "under control" but still a problem, and it pains them to no-end. They seek advice and chizuk, but if they really want to stop, they also come to GYE for the opportunity to admit - and thereby confront - the whole truth about themselves before it grows to proportions they'd rather not face, at all.
Some members concede that they are doing aveiros, but consider their main problem "a lifestyle of sin". They see that correcting individual aveiros as not enough for them - they sense that they need an overhaul of their entire perspective on kedushas habris, or maybe even on serving Hashem. They also come to GYE for the honesty, chizuk and eitzos. Perhaps GYE will help them make strong friendships that will guide them to the lifelong help they will need to serve Hashem truly.
Other members sense that their lives are actually out of control because of their lust habits. They may not yet have lost jobs or homes, but they doubt that even those ends are far off. They suffer with the knowledge that they live a double-life. Good, trustworthy, frum people on their outside - but they know the trance they get into pursuing their next high - and that they are like different people then. They hide their activities. At first they see the privacy as discretion, later they discover they are actually hiding in order to protect their ability to keep doing it! They truly wish to serve Hashem, but know that they could not possibly live like other servants of Hashem do - unless they can take their drug along...
These folks are often addicts, identical to the alcoholics and heroin-users. True, my body odor typically doesn't bother me much, but there is really no difference in the methods and desperation of SA's to AA's. And they too only get worse, never better. There ain't no easy way out.
This last group can find resources, advice and chizuk at GYE, too. They may get help to face to truth about themselves - whatever it may be, and to get the help they really need to save their lives. Often there are wives', husbands' and children's lives in the balance, as well. I am glad that GYE does not decide for members what they need, but members are encouraged to share what actually works for them, rather than simply 'teaching' more true and good hashkofa. (Hey, you can go anywhere for that!) Many addicts feel they need to know where even abject losers go to become 'winners'. I am one of those losers, who found help in one of the resources that is made available by GYE.
So, to your question: Of course, the standard of halacha is simple and clear. But once you ask about "defining staying clean" it depends on what you are coming from, and will change and grow as you do. "How do you define staying clean?" I'd answer by saying that it truly depends on what you consider your 'dirt'.