Well, in all my years as a civilian, I have never once had a drug test, other then as a "pre-employment screening". For Hughes, Boeing, Disney, and a few others they were required. But I never once had to take a follow-up test. And nobody I know of has ever had one either (unless they were working as a driver).

And trust me, I know how civilian life works just fine. I spent 14 years as a civilian (1993-2007), and did quite well. I simply came back to the military, where I was happiest, and where I felt like I could make a contribution more then building or repairing yet another computer or network.