There are loads of things to potentially go wrong with a flashlight but most, are thankfully, either minor or easily rectifiable. The brands I trust most are American made and are Surefire with a Malkoff dropin, Maglite with a Malkoff dropin and First Light. I have a Pelican 8060 which seems to be equal to the other lights in the reliability stakes but somehow the plastic doesn't instill me with confidence if it was to be dropped onto concrete on a cold day. I don't use European lights but I know from recommendations that Wiseled are pretty darn bullet proof. I have one Chinese made light, a Nitecore EA4 which is pretty battered but still works fine. For when I'm out I always believe in the old saying 'one is none and two are one', so I guess as long as I've got any of the brands above I feel confident I'd get home OK.