Keys
There was a time in history that a man’s home could be made secure with a peg above a door latch or by withdrawing a leather thong back inside of the cabin, but no longer. Slowly men created ever more ingenious ways with different contraptions. Securing the home for valuables was the main reason. As mankind became less of hunter-gatherers and settled down as farmers, they accumulated more things. They were less likely to travel and less likely to have their belongings to be light enough to transport. As houses, furniture, cooking areas, and bedding became stationary, they needed to be protected from marauding animals, weather, and other human beings.
People gathered more and more things in homes, barns, or storage areas that were of value or necessity and doors became important. Doors needed to be made secure more that a latch could afford. The latch slowly evolved into increasingly more integral inventions. Some created locks had a wooden key to turn the hidden tumblers. They were replaced by metal contrivances and used a metal key to open the lock.
I can remember growing up, the door to our house was locked and could be opened by a skeleton key. Even though we rarely locked our doors, it gave a false feeling of security. Why, because those keys were basically universal. Everyone in the neighborhood had the same key for their home’s door also. If you lost your key, I imagine that you could go next door and borrow theirs. But then again, we rarely locked our doors.
Locks evolved with each door needing separate keys. Can you remember having one key for the front door or the back of the house or the garage and one for the ignition and one for the glove-box of your car and trunk? Locking your keys inside happened only rarely.
Now keys have been replaced by key-fobs. The computer in the car tells the auto whether the key-fob is inside of the vehicle. The push button starter will not respond without the fob being present.
The doors of homes today can be accessed by your cell phone. The phone can be used to turn on or off lights. The phone can open the garage door. I imagine you could even program your phone to have a cup of coffee ready for you when you arrive at home.