RE: Head Shots...is there a time
Of course there is a time, it also depends on your weapon and target...
I use head shots a lot, when I predator hunt at night, put the crosshairs of my 223 right between the bright eyes. Of course I practice shooting it at night w/ my light set up just like when hunting. I can get a 4 shot group in the size of a dime at 100 yrds, so I'm confident.
Also for geese/ducks/turkeys I always use a head shot...