I don't find i get addicted to stuff either. When i went travelling last summer i was smoking a pack a day for a month but quit without any problems when i got home. i only ever get cravings after i've been drinking.
Same with coffee, i've had around a month and a half of solid uni work, essays in, lab writeups to complete and the last three weeks have been finals. I've been drinking about 6-7 coffee's a day plus pro plus (caffeine pills) between coffees but i know that as soon as i finish my exams i'll just stop. Although life will be so chill that i won't need the alertness that i can probably only get with caffeine
With addictive substances i find i will binge on them for a month or so and then quit completely, no cold turkey.