well the longer you have the better. Look, you get out what you put in. The longer you go without smoking, the more effort you put into cleaning out our body the better chance of passing the test. The bodies natural cleaning system works great! lots of fluids and lots of sweating! Mature people would stop smoking and detox the body. I use the test cheats as a last resort... I say this because going for a job is not as important as passing something for the govt. I would do everything in my power to not smoke and clean in her position but its hard to convince someone that has two dui's logic!