Over the years I have found – prosaically – that the two most useful items to put in my hand baggage are ziplock plastic bags (in assorted sizes) and superglue (things often get broken when you travel).
I also carry a Leatherman in my suitcase, which has a variety of tools, the most useful of which is a tiny screwdriver with which to reassemble your sunglasses when the little screws fall out. The crucial thing to remember about a Leatherman is that it does not contain a corkscrew. Other gadgets I always carry include a small but powerful Maglite torch (flashlight), a smartphone and a universal adaptor plug.
Buy Now: $29 Leatherman $19 Maglight Flashlight $38 Universal Adaptor
The single thing that most improves life at airports is wearing loafers or deck shoes. Many people seem to travel in trainers and therefore are obliged to lace and unlace them going through security. This is annoying for themselves and everyone else.
Noise-canceling headphones really do work and are, in my view, a mandatory purchase. Alas, they are hopeless for sleeping in, so foam earplugs remain a necessity. Rather than relying on the airline, however, take your own preferred earplugs and eyeshade. A scarf can also work to shade your eyes, and I bring one in any case to combat the inevitable chill of an airplane.
Buy Now: $300 Bose Headphones $235 Scarf $13 Eye Mask/Earplugs
It is generally a mistake to imagine that you will be able to buy decent sunscreen when you arrive. Most hotels gift shops have either factor 4 or factor 50 and nothing in between. Also, many people, myself included, are allergic to cheap brands. Over the years I have come to the conclusion that the best sun products are made by Clarins.
On safari, everyone remembers to take a camera – although many people neglect the mandatory 300mm lens – forgetting that the really essential piece of kit is a pair of good binoculars. Friends who own safari camps have traditionally sworn by Leitz products. However, if money is no object, I suggest you opt for Swarovski’s EL 8.5×42. Also remember to take your own bird identification books and field guides; the lodges never have enough copies.