If you’re in transit and have friends or colleagues travelling with you, ask someone responsible to carry one of the hard drive backups for you as well. That puts two backups with you and one with a friend. And by all means, if you’re flying to the next destination, never place your hard drives in checked luggage. Always pack them in a carry on bag.
For more remote destinations or when you’re hiking and camping for multiple days, keep them in dry bags just in case you get caught in a storm, and I don’t just mean rain, in the desert, I’ve found myself caught in dust storms as well. Do your best to protect them from the elements.
I often feel that the photos I’ve captured are more important and valuable than the camera gear itself. Above all – from the moment you leave on a trip to the moment you return – keep your cards and hard drives as safe as possible.