The Ten Essentials/Gear
Knowing what to bring with you on an outdoor excursion is maybe the most important--and most expensive--part of planning a trip. The "Ten Essentials" boils it down into a relatively understandable list that will, for the most part, ensure you have a safe and fun outing. Remember, though, any piece of gear is only useful if you know how to use it, so nothing on this list takes the place of experience.
In an ideal world, even on a day-long outing, you would have everything on this list, in the worst-case scenario that you get lost and have to spend an unexpected night out. In reality, most people don't, although it would likely prevent many accidents from occurring. In any case, for each essential item, we provided a brief explanation of what you might need for a backpacking trip or for a day hike. In the tips page, we provided a list of gear that we took on our most recent backpacking trip (including food).
This website provides a better explanation than our page--https://www.rei.com/learn/expert-advice/ten-essentials.html
Day Trips: Nowadays, most people's main form of navigation is their phone, and whatever GPS app they like to use the most. Trails in China, and Yunnan especially, are almost NEVER marked, so this is especially important. I recommend researching your route ahead of time (using this website, Google Earth, maps.me, etc.), downloading a GPX file of the trail, uploading it into whatever app you use (alltrails, maps.me, 两步户外助手, topo maps+, etc.) and making sure your map is accessible offline. Many trails won't have service, so make sure you can use your map in airplane mode.
Overnight Trips: Still your phone, but having some sort of backup is a good idea, like a map and compass (old school), GPS device or watch, etc. Also, make sure you bring a power-bank, not so that you can continue to take pictures or listen to music in the tent, but so that if your phone dies your map doesn't die with it.
Other notes: Unlike many other things on this list, navigation is a skill that normally takes a bit of practice to develop. Reading a map (even on your phone), reading topographic features, using a compass to take a bearing, understanding GPS coordinates, etc., are all really important to learn, especially if going without a guide.
Day Trips: Headlamp might not seem necessary, but if you get stuck our longer than normal and have to find your way back in the dark, it could make the difference between spending the night and making it back. It's easy to carry, so might as well always bring it along.
Overnight Trips: Headlamp with extra batteries (or a rechargeable one).
Other notes: Check this website for a detailed guide on how to choose a headlamp:
3: Sun Protection
Day Trips: Sunscreen, sunglasses, hat with visor. Lathering up head to toe with sun cream might seem like the best protection, but covering up is actually the better, and safer bet with sun-protection clothing.
Overnight Trips: Same, but carrying sunscreen can be a pain, which makes sun-protection clothing your ally.
Other notes: If you plan to encounter snow, sun protection is even more necessary, as you're getting hit from above and below when standing on it. Good sunglasses are a must to avoid snow blindness.
4: First Aid
Day Trips: Most people probably forgo this for day hikes, but it's a good idea to always carry the basics--adhesive bandages, antibiotic ointment, alcohol wipes, blister care, gauze, tape, basic pain medications. A pre-packed kit will have everything you need, including a guide on how to use it for basic injuries.
Overnight Trips: The length of your trip, how remote you will be, and the number of people involved will all affect how extensive your first aid kit. Like all things, nothing is a replacement for training and knowledge--Wilderness First Aid is a great certification for anyone wanting to learn more.
5: Tools--Pocket Knife
Day Trips: Another one that people often don't bother to bring on day trips, but could become necessary if you were to get lost or stuck out. A Gerber Multitool or a Leatherman is, obviously, versatile, but a regular decent quality knife is good enough, and can help with first aid, cooking, making fires, or any number of things.
Overnight Trips: A good knife is necessary, but the longer your trip, the more you might want things like duct tape, gear repair kits, rope, etc. All of this is available in lightweight form.
Day Trips: A lighter or matches is all you need here, for emergency use only.
Overnight Trips: Most people cook while backpacking (even though it's not completely necessary), which normally requires the use of the stove. There are many options--heavy or light--for stoves. Cooking over a fire can be nice, but when there's no fire pit, campfires are only for emergencies.
Other notes: The long lost art of friction fires render all of this unnecessary, but who wants to learn that.
Day Trips: Okay, nobody brings a tent on a day hike "just in case", but lightweight tarp, an emergency blanket (5 square inches and a couple ounces), or even a garbage bag, could be the difference between life and death on a cold wet night. It wouldn't hurt to know how to build w bush-craft shelter using found items in the woods, either.
Overnight Trips: Obviously, a tent is the go-to option here.
Day Trips: Lightweight, high energy foods like candy or granola bars, nuts, dried fruits and meat, etc. Pack a little bit more than what you plan to eat that day.
Overnight Trips: Food planning for backpacking trips is an art form, and many people spend most of their planning time figuring out their meals. For emergency purposes, a good rule of thumb is to pack an extra day's worth of food.
Other notes: See this website for excellent food planning tips--https://www.rei.com/learn/expert-advice/planning-menu.html
Day Trips: Bring as much water as you think you will drink that day, which for most people is around "half-liter per hour during moderate activity in moderate temperature". Also bring a way to treat water, in case you need to re-fill in an emergency or just because you underestimated your own consumption.
Overnight Trips: A reliable way to treat water is the most important here, as you obviously won't carry multiple days worth of water from the trailhead. There are a lot of water purification options out there. Knowledge of water sources along the trail is arguable even more important (FYI this information is very difficult to find in Yunnan for more remote trails).
Day Trips: Extra clothes that would keep you warm enough if you had to spend a night out. along with maybe an emergency blanket (part of #7 and 4). Rain gear is important and falls in this category, since it keeps you dry, which keeps you warm.
Overnight Trips: It's colder at night, so you need more warmth. A good sleeping bag and a good sleeping pad, warm base layers, hats and gloves, in addition to all the warm layers mentioned above. Here is some advice on how to dress in layers: https://www.rei.com/learn/expert-advice/layering-basics.html