I’ve noticed that if I say “I won’t do this anymore at all”, it doesn’t work. But if I say “I’ll only spend this much this month on sex workers, gambling, etc.” I’m able to mellow down. I’ve also noticed some people suggest that moderation doesn’t work and you should try to be as cold turkey as possible.
In my opinion, addiction is a relationship. Sometimes it’s hot, sometimes it’s comfortable, sometimes it’s a nightmare. It all depends on the combination of influences involved.
So, yes, moderation works as long as circumstances allow for it. Depending on the addiction, the bad times can still be pretty manageable. Or not.
In the words of William S. Burroughs, there’s nothing recreational about heroin.