This is a great subject to start a thread about. I always thought that even among medfetters who like the physicals they got growing up I was alone in thinking back on the moments of finding out I had one scheduled. Sometimes, like for school sports physicals, I had plenty of notice because a letter and then a follow-up letter would be sent to parents by the school and parents had to sign a consent form and then I had to bring that back to school personally well in advance of the physical. For ones that my parents took me to, I think I usually had a few weeks' notice and, since it was usually for me and my brothers at the same time, there would be a note on the calendar like, "boys appt. w/Dr. So and So." And usually the appointment card mailed back by the clinic with more details like the time of day etc. would be clipped to the calendar.
One of the most memorable ones I ever had, though, I only found out about minutes before it happened. I posted about it here before. My parents picked me and my younger brother up after school. His elem. school (he was 11 but almost 12 at this time) was right adjacent to my school (I was 13, almost 14) and then we drove to this big medical office where we had been a couple of times after getting sick or hurt. But this was for my younger brother to get a physical. I was already in a bad mood about a lot of things and having to go along for the ride for this made it worse (I was going through a moody adolescent phase where I wanted everyone to know how gloomy I was I guess). So, we sat for a long time in the waiting room and then the youngish male physicians' assistant who worked there came out and called my brother's name and said for my parents to go back with them as well. My parents told me to stay put. I even remember that there was a TV in the waiting room with some afternoon talk show which I had no interest in. I sat there playing with one of those old handheld water games (this was early 1980s) where you press little buttons to get rings around posts. So, after sitting there for what seemed like 30-45 minutes, the PA came back out and said, "Jake?" and I looked up and he said, "come on back here with me." This only annoyed me more because what I THOUGHT was happening is they didn't want an unattended kid in the waiting room and I was at an age where I hated being thought of as a kid. So, I even said, probably being grumpy at him, "how come I can't wait out here?" and he said, "the doctor and your mom and dad decided you are going to see the doctor while you are here too." And I whined, asking why, and he said that since our parents have brought us in for a few little things in the past and we were still "new patients" that "the doctor needs to give you a complete physical to get to know you." So, I whined some more and said I had just had one for sports at school and told him "I don't want to get a physical today," and he said, "well, you don't really have any say in it. It's your parents' decision."