So you might have the luxury of a vehicle or a raft to take everything but the kitchen sink. The raft on our trip through Dinosaur Park in Wyoming (picture below) even made space for an ice-cream cooler! But most serious travellers keep it to light and essential items that have earned their place in your pack or boat. (the picture above shows a lighter form of raft trip, this time in Colorado for two weeks). I'm asked about kit quite often when I do talks but especially by 'gappies' heading off on their first adventure. Of course it very much depends on where you're going but below is my 'must have' list of items that invariably find their way onto every trip, whether in the UK, USA or Himalaya. As always comments are always welcome and clicking on the image will take you to the UK Amazon store.
Silk sleeping Bag liner
These are much lighter than the cotton variety and simply essential. In hot climates you can sleep in them and I have been trekking in Nepal with this and no sleeping bag. (you can find blankets in every teahouse if it gets cold). If you are using a sleeping bag then it's another layer of insulation and cleaning your liner is a lot easier than the bag itself. They're quite expensive but they will last years and for those on gap year adventures staying in less salubrious hostels they will save you getting plagued by bed mites - not a pleasant experience.
They may not be the most absorbent towels but they are lightweight and hard wearing. They also double up as a pillow cover and something to sit on. I know others find a 'sarong' similarly useful, both as an extra garment and multiple other uses such as covering up in Muslim countries. Beware, regular towels are heavy items of kit.
There are lots of varieties of these chargers available now and I have written a longer review about chargers here. Make sure you get one that is adequate for your needs and although they are on the weighty side they are a lot easier than messing around with solar panels. Be sure to keep it tucked away though, as annoyingly you'll find yourself in great demand when less organised travellers have their phone run flat!
Swiss Army penknife
I'm still a real fan of these despite the onset of the much weightier multi-tools such as Leathermans and Gerbers. If I was cycling then a multi-tool can prove genuinely useful but most of the time there is simply no need. Do you really need a pair of pliers or a hacksaw blade? My trusty penknife is very lightweight and the little tweezers which stow away and the bottle opener will see you through most of what you need. And of course the knife!
I have several of these primarily for river trips but they are tough and incredibly useful for any expedition. I find myself using them repeatedly for valuables. They seem to offer that extra level of security and for several smaller items, such as repair kits, or even dirty laundry they are brilliant. They can also usefully be slung across the shoulder for day hikes when you don't want to carry your sac.
I resisted using one of these for a while as with modern LEDs the AAA batteries that most take will last quite a while. You can also get batteries the world over of course. But two things changed my mind. Firstly batteries are one of the trickiest items to recycle and if you're high in the Himalaya or on a river it's pretty irresponsible to be binning them en route. Secondly if you're taking other USB charging devices such as a smartphone or a GoPro then some method of charging them (such as the charger above) is essential. At 1800 mAh the capacity of one of these torches is about the same as an iPhone. If you have an old Petzl as well you can always swap the normal battery pack in anyway.
Filtered drinking water
If like me you find chorine tablets a hassle - as well as unpleasant in taste - then this is a great solution. Aside from use in the wilderness it's brilliant for hotel rooms where you can't trust the tap water. With each filter good for 180 litres it will see most travellers through an extended trip. Remember that using mineral water, especially on the trail, does nothing for the world's plastic litter problem.
All purpose soap
Reduce the weight of multiple bottles and toiletries by taking one good quality soap. This is good for showering and washing clothes and is biodegradable. There seems to be a craze in Nepal at the moment for trekkers to bring wet wipes for convenience. Please spare a thought for the environment and countries where there is no litter collection to speak of.
I like this adapter as it has a couple of USB ports in addition to the regular connections. A really useful bit of kit and it can be used in reverse back in the UK if you have an appliance bought on your travels.
Travel Wash kit
These are really useful, if only for the hanging hook and small mirror when you're in something that lays claim to be a shower. The zipped pouches are also great for first aid items and a small sewing kit.