As mentor and former teacher advised me when I was looking to get into education, “never do anything for free. The moment you do, that is when admin expect you to do more than what you’re paid to do.” You are correct that roughly 75% of what we do outside of the normal school day is voluntary unless the district recognizes those extra hour and tries to compensate for them. Most of us do not mind the extra time but I have started to just because that is time away from my family and family time is becoming more important everyday for me.