I'm in a very similiar situation to the thread starter. I personally know that I'm not dependent on marijuana, and I used to smoke ~5x a day. The first 5 months of my probation I was randomly drug tested and did not even look at it the whole time. Since I got back to college, I have been drug tested every 2 weeks, and I have found that 14 days is plenty of time for me to smoke and pass my UA with flying colors. Granted, I'm a small guy (5'9 135)... Anyways, I think your labeling of people who smoke on probation as people with a dependancy on smoking is innacurate unless they are randomly drug tested and still continue to smoke. I've passed about 7 UA's now, never even messed with dilution or anything...I think I'm ok.