Very rarely and only when absolutely necessary. I can count on 1 hand the number of times in the last 3 years or so and only in group situations.
The way I optimize a group shot so as to avoid closed eyes, goofy expressions, etc, is I have everyone train their eyes right on my lens and then tell them close their eyes and think of something pleasant. After a second or two everyone's gaze will relax and take on a natural, relaxed expression. I then tell them I'm going to count "one, two, three, open" and without moving or changing anything they are to open their eyes on the "open" command. I count it down and hit the shutter a beat after I command "open". I get about a 99% success rate with this technique. I'll shoot 2, maybe three frames just for insurance but can pretty much guarantee that I got a workable shot that won't require compositing to fix.