Santa Barbara in December

Merino or synthetic, since this is the layer that sits under everything else and cotton stays wet.

PatagoniaPatagonia Capilene Cool Merino Blend Long-Sleeve - Women's$62.30Shop at Backcountry →Mountain HardwearMountain Hardwear Chillaction Long-Sleeve Crew - Women's$44.99Shop at Mountain Hardwear →SimondSimond Merino Resist Long-Sleeve T-Shirt - Men's$45Shop at Decathlon →ColumbiaColumbia Summit Valley Long-Sleeve Crew - Women's$24.75Shop at Backcountry →

Merino, not cotton. It stays warm when it's damp and still doesn't smell on day three.

Arc'teryxArc'teryx Women's Satoro Merino Wool Crew Neck Long-Sleeve Base Layer Top$95.73 was $120Shop at REI →REI Co-opREI Co-op Women's Merino 185 Long-Sleeve Crew Base Layer Top$84.95Shop at REI →WedzeWedze Women's BL900 Merino Wool Ski Base Layer Top$60 was $99.99Shop at Decathlon →TerramarTerramar Men's 3.0 Merino Bi-Layer Long-Sleeve Crew Base Layer Top$29.73 was $45Shop at REI →

One pair for every two days, plus two.

SmartwoolEveryday Merino Thong Underwear - Women's$34Shop at Backcountry →SmartwoolEveryday Merino Bikini Underwear - Women's$34Shop at Backcountry →SimondSimond Trek 500 Merino Wool Backpacking Underwear Women's$29.99Shop at Decathlon →REI Co-opREI Co-op Women's Merino Hipster Underwear$29.95Shop at REI →

Trail runners dry overnight where boots take days, which is why most people prefer them on warm trails.

CraftCraft Women's Endurance Trail-Running Shoes$130 was $175Shop at REI →KiprunKiprun Kipsummit Max Women's Trail Running Shoes$150Shop at Decathlon →KiprunKiprun Kipride Women's Running Shoes$140Shop at Decathlon →QuechuaQuechua Men's MH100 Hiking Shoes$45 was $64.99Shop at Decathlon →

Buy it used: REI Re/Supply sells gear like this for less. See used gear

Bring the pair you already walk ten miles in. Brand new shoes on day one is how the blisters start.

NnormalKjerag Shoe$109 was $140Shop at Backcountry →SaolaQuito Shoe - Men's$130Shop at Backcountry →ScarpaMojito Bio Shoe$59.68 was $199Shop at Backcountry →SaolaEzo Shoe - Men's$83.96 was $120Shop at Backcountry →

Polarized kills glare, but the tag has to say 100% UV separately, and that's the part your eyes need.

SmithSmith Cheetah Polarized Sunglasses - Women's$93 was $155Shop at Backcountry →ZealZeal Isabelle Polarized Sunglasses - Women's$67.03 was $149Shop at Backcountry →Ray-BanRay-Ban Wayfarer Oval Polarized Sunglasses - Women's$171 was $244Shop at Backcountry →KnockaroundKnockaround Junipers Polarized Sunglasses - Women's$17.50 was $35Shop at Backcountry →

10,000mAh is about two phone charges, 5,000 barely gets you through one long day.

Top pickGoal ZeroGoal Zero Venture 75 Power Bank$120Shop at REI →BioLiteBioLite Charge 80 PD Power Bank$99.95Shop at REI →AnkerAnker Zolo Power Bank (20,000 mAh, 22.5W, Built-In USB-C Cable)$40Shop at REI →AnkerAnker Power Bank (30W, Fusion, Built-In USB-C Cable)$40Shop at REI →

REI members usually get 10% back on full-price gear. Membership is $30, once. How it works

65W or more charges a laptop. Anything smaller only keeps up with phones.

Peak DesignPeak Design 65W Dual Slim Charger$64.95Shop at REI →Peak DesignDual Slim Charger$64.95Shop at Peak Design →AnkerAnker Wall Charger (33W, 2-Port) with USB-C to USB-C Cable$25Shop at REI →AnkerAnker MagGo Wireless Charging Station (3-in-1, Foldable Pad) with Charger and USB-C Cable$100Shop at REI →

35 to 45 liters fits most cabins. Check your airline's size limit first. Most won't take much over 40L in the cabin.

Top pickMatadorMatador 45L Global Travel PackSee price15% off with CHRISANDSARAShop at Matador →PacsafeGo Carry-On 44L Backpack$180Shop at Backcountry →Osprey PacksOsprey Packs Archeon 30L Backpack$132 was $265Shop at Backcountry →MatadorMatador GloberiderSee price15% off with CHRISANDSARAShop at Matador →

Hard shell protects what's inside, soft shell squeezes into a tight bin, and either way check the size with wheels included.

CotopaxiCoraza Suitcase - Carry On$295Shop at Cotopaxi →SamsoniteFreeform Spinner$154 was $220Shop at Samsonite →SamsoniteHyperflex ∞ Carry-On Spinner$126 was $180Shop at Samsonite →ThuleThule Aion Carry On Spinner Nutria$350Shop at Backcountry →

15 to 25 liters.

CotopaxiConsuelo 22L Daypack$120Shop at Cotopaxi →CotopaxiElqui 24L Daypack$100Shop at Cotopaxi →MammutLithium 20L Daypack$135Shop at Backcountry →StioStio Basin Daypack$75.93 was $109Shop at REI →

Look for a locking zip and a strap with a steel cable inside. That's the part that stops a snatch.

Matador2L Lite Sling$22.99Shop at Backcountry →Peak DesignCity Sling$69.95Shop at Peak Design →PacsafePacsafe GO Anti-theft Saddle Crossbody$79.95Shop at REI →CotopaxiEmpacable 3L Sling$50Shop at Cotopaxi →

Get locks marked TSA approved. Security can cut anything else off to search your bag.

MatadorMatador BetaLockSee price15% off with CHRISANDSARAShop at Matador →PacsafePacsafe ProSafe 620 TSA Accepted Luggage Locks$17.95Shop at REI →KnackKnack TSA-Approved Lock$16Shop at Knack Bags →PacsafePacsafe ProSafe 1000 TSA Combination Luggage Lock$17.95Shop at REI →

It runs on Find My, so this one's for iPhones.

AppleApple AirTag (2nd Gen, 4-Pack)$95.99Shop at B&H Photo →eufyeufy SmartTrack Link (2-Pack)$19.99Shop at B&H Photo →AppleApple AirTag (2nd Gen)$29Shop at B&H Photo →

Hydrocolloid blister plasters, not regular ones. They cushion the blister and stay on for days, even in wet socks.

SpencoSpenco 2nd Skin Blister Kit$14.95Shop at REI →Adventure Medical KitsAdventure Medical Kits Blister Medic Kit$15.95Shop at REI →Adventure Medical KitsAdventure Medical Kits Moleskin Blister Dressing$10.50Shop at REI →HART OutdoorHART Outdoor Blister Kit$9.95Shop at REI →

Rechargeable over USB-C, so it shares a cable with everything else you carry.

BioLiteBioLite Dash 450 USB-C Rechargeable Running Headlamp$69.95Shop at REI →BioLiteDash 450 Rechargeable HeadLamp$69.95Shop at Backcountry →FenixFenix HM50R V2.0 Rechargeable Headlamp$59.95Shop at REI →Black DiamondStorm 450 Headlamp$38.47 was $69.95Shop at Backcountry →