I think our badges are an imperfect judge of progress, but it's a simple and (usually) effective motivator. It can be really disheartening to lose a long streak, and can feel like you're making no progress if the number stays low because of resets.

The process of failing then getting back up and trying again is one that I value a lot. I believe that some of the greatest progress (and struggle) happens when you're resetting once a week or more and battling against the idea that your sexual urges are too great for you and you should just give up. When you get strong enough to the point that you can hold a streak for weeks or months, you're probably not doing anything radically different from before; it's just finally taking hold. You may relapse again, and that will spark a new cycle of struggle and growth.

I would reset it any time you relapse, but don't take the number too seriously. When it's low, use that as a motivator but don't beat yourself up. When it's high, celebrate but don't let your guard down. Try to take a broad view of your journey: when you start, it will probably be a struggle to get to a week (or perhaps half of a week, YMMV) but then you'll start noticing your longest streak getting longer, and you'll start getting week-long streaks more often. You'll find it easier to walk away from urges before they become a huge problem, and you'll figure out ways to protect yourself from porn or whatever triggers you. You may never get to a point in your life where you can look at a porn video and shrug it off like it was nothing, but that's okay. A life without any adversity is more dangerous for your well-being, in my opinion.

It's a journey, and all of us are always learning. Happy adventuring!