From 1979 to 1997 I worked for a contractor that did a lot of classified work for DOD and DOE. I received a Q clearance in 1979 and held it until about 1995, so my experience is not recent. If I remember correctly, mine took about 3 months. This may vary a lot, especially as you were born in another country. The experience was interesting, but not intimidating. The key is to answer all questions honestly and completely.The interview process started with a long questionnaire on my life history, followed several weeks later by an interview with several federal agents. Part of the questionnaire asked about all the places I had lived and worked over the last x-many years. They really meant ALL the places. I had left out a two-week period when I was between apartments and jobs and was staying with a friend. A major focus of the oral interview was that two-week period, and they sent agents to verify my answers. They also personally interviewed all my references, some of my neighbors and former neighbors, and some of my parents‡ neighbors.My only travel outside the US was two one-day trips to Canada with my parents, so that was not an issue.Several questions were asked about contacts with, or attendance at conferences with nationals of potentially hostile countries. As a chemist, I had had a few casual contacts with chemists from Czechoslovakia, Poland, etc., but this did not seem to raise any flags.One question dealt with membership in subversive organizations. The questionnaire provided a list of such organizations. To my surprise, Consumer’s Union, the publisher of Consumer Reports, was listed as a Communist-front organization, so I had to check that one. The agents thought that that was as silly as I did.One section dealt with criminal history. I had never been arrested or accused of a crime, so that raised no flags. Several people that applied for Q-clearances about the same time I did had some history of minor drug use. They still got their clearances.I was a little surprised about some of the questions that WEREN’T asked. No questions were asked about sexual history (not that I had much to tell). I served as a reference for a friend from grad school that was also applying for a Q-clearance. The agents asked what he did in his spare time. I told them that he was very active in his church. The agents cut me off immediately. They told me they could not ask, nor could they record, any information about religious, political, or labor organizing activities.