How long does benzos stay in your system?

Drug approximate detection time in urine for benzo's are 2-30 days, if you want a more specific answer, Wiki the drug name, look at its half-life, if its 12 hours half the mgs will metabolize every 12 hours, and so on, and so on, then it depends on what the trace level detection is, when you keep dividing a number you keep adding zeros before the decimal point, you're not safe until its below detection level.

benzodiazapines are notorious for staying the system for weeks and sometimes longer. I have seen people test positive 6 weeks after a last dose. If you don't have a prescription then you should really stay away from them as they can be dangerous and are going the way of the barbiturate...