I travel alot with my gear and I never check it in. Always always always carry on! All my camera equipment, laptop etc is in my handluggage. I use the Loewepro combo trekker, and I can almost fit everything in there: Ikelite housing, 2 lenses, flatport, 8 inch domeport, 1 Inon strobe all cables etc. (My girlfriend can carry the leftovers that doesnt fit - second strobe and an extra lens! ) My handluggage - fully packed with laptop in the back weighs around 16kg - but never have I been asked to put it on a wheight-scale. I have it on my back when I come to the check-in counter, and try to look like its lite as a feather! I mainly travel from Europe to the red sea or asia. Only one time in Borneo, have I been asked to put my handluggage on a scale and when they asked whats inside and I said camera and computer - well they didnt mind anything about it.