Hi Mike,
Welcome to ETS. Please enjoy your visits and come back often. You will most likely find that we are a pretty friendly bunch and hopefully you will enjoy the camadarie and information that is available.
With respect to the question that you posed, KI6IW has pretty much set the common theme for being prepared. If you prepare for something, anybody can always "Monday morning quarterback" with 20-20 hindsight and say that if you had this or that (or done this or that) you would have been better off. And in many cases this will likely be true.
However, like many other things in life, this can be carried to extremes...i.e. it would seem that you could have everything that you could pack into an ocean liner (in order to be prepared when the planned outing is just to cruise around Key Largo for half a day) and still be short of something. The extra energy and resouces that you applied to the trip would not be commesurate with the enjoyment of that cruise.
Please understand that I'm not by any means advocating going unprepared, just simply stating that one's preparations should be in line (and practical) with the planned activity. A walk in a city park to go fly kites is not the normal time that one would require a PLB, however having one with you when spending a day backpacking in the wilderness would be a more likely venue for needing it.
In reality, it is doubtful that anyone could ever be prepared for everything all the time and everywhere that they might find themselves. The point is to be as PREPARED AS PRACTICAL for the time and place that you expect to be going.
It is really kind of like buying insurance, you never hope you need it, but it is there just in case. The bottom line is that you never see the accident that you've prevented by being prepared properly.
Hope this helps answer your question.
Regards,
Comanche7