I'd say you're a stoner when you skip a day, and you're like "Dude it's been so long since I've smoked" the day after. And then of course you realize it's only been 1 day when it feels like a week.

I'm okay with stoner, but I wouldn't like to be called a pothead. Doesn't pothead kind of imply pot has taken over your brain? Think of the possible origins of the word.