For those who are working loads down to a minimum functioning load, squibs can certainly be a fairly common occurrence. A guy who is searching for that mouse load, for what ever reason, is, or should be expecting to have a few now and then. But that type of work up, or down as it may better be described, has a limited risk when being performed by someone that is on the constant watch for such, as he is actually trying to locate that defining marker, no problem I would think.
But for the average every day reloader that is working with published data, they should not ever feel that squibs are just a part of the risk involved in this hobby. With the massive increase in the number of shooters that are taking up reloading, I have seen a growing problem with regard to reloading safety. And it doesn't just end with, or involve squibs, there are a number of other very serious and preventable issues I'm hearing about that greatly contributes to the apprehension I'm feeling more recently.
My fairly recent post about having confidence in your reloads, sums it up in a nut shell. I truly believe that any reloader who is doing things in accordance with common sense, and attention to detail, will have an uneventful life of reloading. But for those who skimmed through the pages of their books, if they bought any, will not. It's not brain surgery, but it can certainly lead to needing brain surgery, and other forms of medical attention, if not afforded the respect this hobby demands of us.
GS