This was my personal experience with "gaps":
I was covered continuously through June 2009 because of my school transcripts, then I took a year and a half after graduation before I went to college. My college transcripts started Jan 2011 until present. When I got the RFE, I was sooo worried about covering all of the months between 2009 and 2010, but the only way to do that would have to be by sending in 18 months worth of bank statements that I didn't wanna wait for, because the bank said it would take 10 business days.
So what I did was send in my medical records. I had had a visit in January, one in May, then August and November. I also found a bill dated for December of that year, and sent it as my RFE as well. Although these 5 items did not prove I was here on every single month, I was still APPROVED after getting my RFE.
So, try to send as much as you can, but dont stress it so much. The officers will use common sense... or so I hope.
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Vermont Service Center - Biometrics walk in: Sept 11 --- (original date Sept 14)
RFE letter printed: Sept 21 --- RFE letter received: Sept 27 ----- RFE letter received at USCIS: Oct 9, 2012
i821 Approval: 10/12 - EAD mailed out 10/15 - EAD received: 10/17