There are certain backpacking essentials you must have if you are planning to take a trip of any length of time.
Even though there are many new modern devices and such out there you can use, there are certain traditional items that you should carry with you.
For instance, if you carry a battery powered GPS and the batteries go dead, you could be in trouble.
This thought leads me into the backpacking essentials which you should take on your trip:

• Map-You should choose a map that is more suited for backpacking or hiking.
  It needs to contain thorough information about the trails and the area of your trip.
  
• Compass-While having a map is important, the compass is an essential companion to the map.
  These two backpacking essentials go hand-in-hand.
  Things can start to look the same out on the trails, so it is important you have a sense of direction.
  You should choose a compass that is durable and will stand up to things such as weather.
  
• Flashlight-Having adequate lighting ensures that you see what lies ahead.
  Having proper lighting can prevent falls or injuries; things which could put a damper on your trip.
  
• Extra food and clothing-There are many situations that can arise while you are out on the trail, so be sure to pack extra food and clothing.
  You should always prepare for the unexpected.
  It's better to be safe than sorry when packing your backpacking essentials.
  
• Knife-A knife is something that you will find many uses for while you are out on the trail.
  If you can afford it, a knife such as Swiss Army knife is a great asset since you can perform many things with it.
  At minimum, you will need a sharp knife that you can use to cut fabric and cord.
  
• Matches-The matches you carry should be waterproof.
  As with everything else, matches are must have backpacking essentials.
  If you do not have access to waterproof matches, make sure you store them in a container which will keep out moisture.
  
• Water or water treatment-You must stay healthy and at your best while you are on the trail, and being hydrated is one of the best ways.
  If you are not going to carry water with you, then you should carry necessary items, such as iodine tablets, to treat the water.
  
• First Aid Kit-I consider this to be one of the most important backpacking essentials.
  You never know what you may run into while you are out on the trails.
  Having a first aid kit is important even for well traveled places or areas you know well.
  You should make sure that the kit is well stocked with a variety of supplies and know how to use all of the content properly.