Unhappy [Q] Nexus 7 3rd bootloop in one year


Last year I bought a Nexus 7 (2012 edition) and I have been very happy with it. But when it turned June, my tablet got stuck in a bootloop. So I downloaded Nexus Root Toolkit and flashed the factory rom again. This fixed the problem and was able to play around with my Nexus again. But in September 2013 the tablet was stuck again in a bootloop, so I did the same with NRT and it worked perfect again. But now, 5 months later it is stuck in a bootloop for the 3rd time. Is it possible that this is caused by a hardware defect? (bad SSD or something??) Anyway, I'm going to hand it in for a warranty repair. Is there anyone who might have an idea what causes these bootloops and whether it's a hardware or software malfunction?

Thanks in advance,