If you are day-hiking on trails, carry a colored ribbon with you - when you come to any fork or trail separation, tie a piece of it on a tree branch, or place tip under a rock - when you return, find the ribbon and your way, and take it out with you ... very light, doesn't add to weight you carry, and might save a life.
Might not work always, or even be appropriate for every occasion, like walking a dog, but you never know ... and of course, doesn't deter foul play, but will give any family or rescuers a "start search" heading if nothing else.
