depends on how long yur hair is or wen was the last time it got cut....
yur hair holds a record of everything you've done, and they are supposedly expensive, wat kind of job do u have? basically, you hair is like a timeline of the drugs youve done, and depends wer u have last cut off that timeline. I heard the only way not to get caught is by shaving your head, otherwise you cant drink anything to make it not sho up :/