I worked with chainsaws for decades without any PPE and have a few small scars to show for it. The first job where chaps were required, I had a mishap that cut through 3 layers of Kevlar on my thigh. Three layers was the minimum requirement. My chaps had five layers.
The first job that mandated a chain brake, I put it to the test when the saw kicked back and almost took off my nose. All I can say is good thing for safety mandates!
You can never be too safe when running a chain saw. I never have a problem (not to say never have) until I take the protective devise off, then it happens usually because I am too hot or uncomfortable. I run a chain saw by myself most of the time and many say that is pushing your luck. I even would not let my dog tag along for fear of him being in the wrong place at the wrong time.