A well packed rucksack carries lighter than a heavy one packed badly. Where you put things decides your balance, your comfort and whether you are still walking upright after three days. Let us go through the pack compartment by compartment.
Bottom compartment
Start with the things you only need once you set up camp in the evening: the small towel, soap, toothbrush, sleeping bag, sleepwear and sleeping mat, at least if it is a smaller inflatable one.
If you have space left, fill it with things you will not need on the move, such as spare food, energy bars or spare underwear.
Never put your head torch in here. Keep that within reach at all times.
Hydration compartment
Right against the back panel there is usually a narrow compartment for your hydration bladder. Newer packs also have a velcro strip to clip the top of the bladder in place so it does not shift as it empties. That is two to three kilos already, and you want it balanced and close to your body.
In the top corners of the pack there is an opening for the drinking tube. Many packs have a clip on the shoulder strap so you can keep the tube within reach while walking.
Load the filled bladder before you pack the rest. Forcing a full bladder in afterwards simply does not work.
The core of the pack
The middle compartment is the largest storage space. How you fill it decides whether you walk steadily or not. Remember: we are trying to avoid back pain and sore muscles.
The heavier items, such as food, water, cook set and a small tent or tarp, belong in the middle of your pack. Do not put heavy items too low or the pack will sag. Put them too high and you become unstable while walking.
So the heaviest item sits just above the bottom compartment and as close to your spine as possible. Lighter items such as spare clothing go around it, keeping the heavy gear in place.
The top of the pack
Most packs have a zip on top. Everything you use regularly belongs there: your first aid kit, head torch, compass, pen, toilet paper, insect repellent, sun cream, sunglasses and the snacks for the day.
The top usually has loops for adjustable straps too. If you carry a foam mat, that is where to fasten it. Make sure it does not push against the back of your head while walking. If it does, tie it with a piece of cord to the lower front of the pack instead, not underneath it.
Side pockets
Side pockets are ideal for longer items. If you carry a larger tent, the poles can go in the side pockets. Make sure the ends cannot pierce the fabric and use the compression straps to secure everything.
Trekking poles fit there too. Point the tips upwards to avoid holes. Some packs have dedicated elastic loops for them.
The front pocket
This is usually a small pocket. Handy for things you want to reach without taking the pack off: a small camera, energy bars, sweets or your phone.
Front loops
Some packs have loops on the front. You can use them to secure extra gear, with a carabiner through one or more loops, or by threading a length of cord through them.
Most packs also have a dedicated loop for an ice axe. Take extra care with that one. Watch which way it points, make sure it cannot pierce your pack and keep the sharp edge away from your body.
Try to hang as little gear as possible on the outside. It compromises your stability, and in dense vegetation you snag on it easily.
Rain cover
Most rain covers sit in a separate compartment at the bottom. You always have to take the pack off to fit one. Be careful in the forest, they tear easily. After the rain stops, leave the cover on until it is completely dry.
A few more tips
Pull all compression straps really tight. The more compact the pack, the better your balance. It also stops the load from shifting.
Fill every empty space. If you carry a cooking pot, stuff it with food, tea bags, small items or even clothing.
Use stuff sacks to compress and protect your clothing. It saves a lot of space, prevents chaos when you are digging for something at the bottom, and keeps your spare clothes dry if you get caught in a downpour.
Share the weight with your walking partners. Food and a tent are easy to split.
And never skip this one on your packing list: duct tape. If your rain cover tears or a strap comes loose, you can still fix something on the trail. Be creative.