In person, the last time I was misgendered was in high school (25+ years ago), online (email mostly) as I have a first name that is typically considered female (however I know easily twice the number of males with the name that I do females) I get misgendered quite often.
As for misgendering someone, I have never intentionally misgendered anyone. In fact I just bumped into one of my customers who recently came out as in transition but his father was not accepting of it and had asked me to continue using his dead name. But now I know he is over 18, so I asked am which I he wanted me to use in public.