Some people go on vacation to relax as thoroughly as possible, some people go on vacation to enrich their cultural knowledge, and some people go on vacation to be as active as possible. Are you the last type of traveler? Has the time finally come for you to kayak with orcas in the Pacific Northwest or to visit Mayan ruins on the Yucatan Peninsula? We are so thrilled for you to take the adventure vacation of your dreams!
Honestly, we are not here to go over your gear with you. Your gear may be highly specialized according to whether you're mountain climbing or white water rafting or hiking the Appalachian Trail, and getting the best performing, safest gear you can from a reputable retailer is our best advice. Know what you'll pack, what you'll rent, and what is provided by your guides if you have them. Read all you can, speak with those more experienced than yourself, and be open to advice. It's also a safe bet that your very first rock climbing trip will not include vertical camping on portaledge hanging off the side of El Capitain, so you will learn more about your gear as you progress in your hobbies, and upgrade accordingly.
Consider the weather carefully before you take off on your trip. Research the area you'll be visiting and know if you're packing for heat, cold, or monsoon season. Scheduling your adventure vacation for advantageous weather conditions is part of planning this sort of trip, so know if you will want mostly shorts and t-shirts or long pants and thermal shirts. A key part of packing for adventure vacations is packing as lightly as possible when it comes to clothing. No one will notice if you're wearing the same few things all the time—it's important to remember why you're taking your trip. Machu Picchu doesn't have a dress code. Find performance clothing featuring quick-dry fabrics. You'll not only be more comfortable if you sweat through them or get soaked with rain, but you can wash out your things in a sink and dry them overnight when you have the opportunity. Literally four outfits of thoroughly mix-and-match items, including the one you wear on the plane, is enough.
One place you should not be sparing with clothing is socks and underwear. If you can't wash out your things, fresh undies will go a long way toward making you feel comfortable, and every adventure traveler knows that wet socks or serious blisters can ruin a trip. Take more socks than you think you'll need, and keep at least one pair in a special waterproof baggie, so if you have a day when everything goes totally wrong, you are at least assured of a dry pair of socks. I have heard climbers refer to these as "sacred socks" and if that's all the warm, dry clothing you can get at a tough moment, I can see why.
All the research on the Internet cannot save you from a pop-up shower or a blustery night. Even if you're packing for a warm, dry climate, you'd better have a good zippered fleece and a quality rain poncho. Every single item you carry should have multiple uses, and, for example, a fleece jacket can keep you warm or pillow your head for a catnap. A poncho takes the place of a rain jacket and a waterproof backpack cover. Wet and cold can be dangerous, so be prepared to face them in a way that keeps you not just comfortable but also safe.
Heat and sun present their own dangers. Have a hat that shades your face, and be sure there is sunscreen among your toiletries.
If you are going to engage in any activity that is even remotely dangerous, get travel insurance that has evacuation coverage. Keep a copy of your policy with your Passport, on your person at all times. Have scans of those on your devices and a Xeroxed hard copy, too, packed in your things in case the originals are lost or ruined. If you adventure internationally, the Passport is an obvious necessity but some people never consider insurance. We hope you never need it, but we cannot urge you strongly enough to have it.
You will need to assemble and carry a first-aid kit. These can be purchased pre-assembled, but you might want "your" kind of adhesive bandages or know that you are prone to heartburn, so packing what you know you use on a regular basis at home is a better place to start than with a convenience-store kit. If you will be far from home, you may have difficulty locating over-the-counter meds you want or supplies you prefer, such as ACE bandages or feminine hygiene products, so pack them in with you.
With planning and care, you can hang glide in Romania or golf across Mongolia (that's a real thing, by the way), so think of the adventure you want to have and go for it! You can survive just fine out of a single backpack, and with the right performance clothing to help keep you warm and dry or cool and shaded, we know there is nothing you can't conquer.