Honestly...not sure I will ever hike alone. Unless it is a popular main trail that gets hiked a lot.
When I was a teen, I worked with search and rescue. I just learned that the risk was not worth it. There is comes more from the if i somehow injured and could not hike out.
Now granted this was prior to cell phones and such.
If i was to hike alone..like others have said, I would make sure I had overnight, emergency blanket etc. Then I would also let someone know where I was hiking,estimated time of rtn. That if I had not checked back in with them by night fall to call emergency services.