I am a weekend hiker and photographer who tries to be reasonably prepared on the trail. Many people have asked what they should carry when hiking. You always hear about the 10 Essentials but I wanted to provide my thoughts on that list. When hiking you should carry a small pack with essential supplies. Most casual hikers bring water, some food, and a small first aid kit. A few additional items can make a HUGE difference should something go wrong. This is my list for basic hiking essentials. Note that this list is NOT a complete or exhaustive but it is a good starting point and includes the things that I carry in my hiking pack.
All of these items can fit comfortably in a medium- to larger-sized hydration pack.
Items in the emergency kit have a shelf life and you need to check them periodically. Plastic can deteriorate, liquids can evaporate, and medicines can lose potency. Space blankets and plastic ponchos are often kept for many years but these can deteriorate especially on the folds. Be sure to check all items in your kit and replace the old and worn items.