When I became involved in SAR many years ago, I gradually began developing a backpack filled with goodies so that I could immediately respond to a situation. The urgency of the calls varied immensely - from "assemble tomorrow at 6 AM to continue the search" to "respond immediately to an injured climber." Duration of the operations lasted anywhere from 0 (on one callout a responder met the subjects of the search on the way to the assembly point) to at least three months plus (this case is still apparently active, 41 years later).

I found it better to respond with unnecessary gear, leaving the unwonted items in my car, that to try and stuff things in at the last minute. But basically, it was Wild West time - anything could happen, including consecutive, unrelated operations.

There were also occasions on recreational excursions where things went awry and having the right stuff available was a real good idea.

Today I am not as involved in SAR as I once was, but the idea of a backpack ready to go still has merit - witness evacuation from the Thomas fire a few years ago. If I have time, I can fine tune the contents, but I can pull through with what is always contained in the bag and my EDC.