Always!!!!
In 2008 I fell while walking down a steep hill. I completely ruptured my left quadriceps tendon and, as a result, didn't have the ability to use my leg from the knee down.
I had a buddy with me (who I contacted by radio) and we used a cell phone to call 911.
Pretty embarassed to say the least. There was a full complement of fire trucks, ambulances, and sheriff's deputies who came to my rescue.
Also now carry one of the SPOT devices.
Don't leave home without either one.
I can't immagine what my incident would have been like without being able to call for help. Not sure that it saved my life, but probably aided in me being able to walk again.
Ken