Should I bring jeans for the evening?

No. Jeans are heavy, bulky, and take days to dry if they get wet. Pack synthetic hiking pants or travel trousers instead.

Is it worth bringing a hydration bladder?

Yes. Staying hydrated is the best way to combat altitude sickness, and a bladder allows you to drink frequently without stopping to pull a bottle from your bag.

How to Pack for the Andes Mountains

Pack using a strict layering system because temperatures swing from 0°C at night to 20°C in direct sun. Focus on moisture-wicking synthetics and wool, leaving all cotton behind as it won't dry in high humidity or cold alpine conditions.

Adopt the Three-Layer System. Bring a moisture-wicking base layer (merino wool), a mid-layer for heat retention (fleece or down jacket), and a windproof/waterproof outer shell. Never rely on one heavy coat; you need to adjust as you move between microclimates.
Select the Right Footwear. Bring broken-in, waterproof hiking boots with high ankle support. The terrain is rocky and uneven; sneakers will not provide the stability required for mountain trails or high-altitude village streets.
Manage Sun Protection. The UV radiation is extreme at high altitudes. Pack a wide-brimmed hat, polarized sunglasses, and at least 60ml of SPF 50+ sunscreen. You will burn faster at 3,000 meters than at sea level.
Organize with Compression Sacks. Use compression sacks to save space. Andes travel often involves small regional planes, cramped buses, and long hikes where your gear must remain compact and protected from unpredictable mountain rain.

Should I bring jeans for the evening?: No. Jeans are heavy, bulky, and take days to dry if they get wet. Pack synthetic hiking pants or travel trousers instead.
Is it worth bringing a hydration bladder?: Yes. Staying hydrated is the best way to combat altitude sickness, and a bladder allows you to drink frequently without stopping to pull a bottle from your bag.