You answer the questions precisely the way they are worded. Up to Secret clearance the 86 requests within 7 years. Beyond Secret the 86 requests up to 10 years. If the question asks have you been arrested within 7 years and you have not, then your answer would obviously be NO. If it appears on your records, of course they will 'find' it. But their concern is for the seven year period preceding your application. If there was something particularly egregious that concerned them beyond the 7 year time frame, I'm sure they will contact you and investigate further. However, the answer is still no, and your answer would still be truthful. As far as "reporting everything" you should report everything that is asked from you. There aren't many places on the 86 to offer more information than they request.

On the sf86 form, it asks if you were arrested in the past 7 years.  When I was a teenager, back in New York state, I had some bad fights w/ my parents and was arrested a few times, w/ no charges pressed ultimately; I talked to a lawyer, and he said that if I had been a youthful offender, it would show up in a background check.   I was never adjudicated as a youthful offender.  This was all over 7 years ago.  I have never been arrested since, never used drugs or had alcohol problems, or anything else other than 2 speeding tickets.

I spoke to some military people on another forum, and they say that DSS can find anything, and that I should report everything.  However, truthfully, I could reply in the negative to Of course, I would report everything to the recruiter.   

My question is: when they only ask for 7 years back for merely arrests?  Will they find everything.  I could honestly say I haven't been arrested in over 7 years.