I'm 22 now, so I reckon I'm qualified to answer this question.
Short answer: Rarely have I had to take off a lot of clothes, but I don't think I would mind if I had to.
Long answer: These are the three exams I had over the course of the last few years from least thorough to most thorough.
My last exam in high school was with three other guys together, but we only got weighed, our height got measured the doctor asked us a few questions. We only had to take off our shoes, nothing else.
Where I live, everyone has to get examined before getting their driving licence. Like at school, I only had to take off my shoes. It was summer so I wore shorts and a t-shirt, but I've heard from friends who took the exam in winter that they had to take off their jumper. This time I was alone with the doctor. He also made me bend forward, and touched my spine pushing up my t-shirt. He also did an ascultation by moving his hand below the t-shirt, but I didn't have to take it off. Then some questions and I was done.
The only other exam I had in the last few years was my mandatory exam for military service, which is compulsory where I live. It was quite thorough, first they tested our hearing, then we all had to enter a big room where we had to take off our shirts. We had to do some physical exercises and they did an ECG. Afterwards they did an x-ray, and only after that we were allowed to put on our shirts again. Then they drew blood, which actually made me faint and panic, so they put me into a private room to calm down. Afterwards we got breakfast and then we had to do some exercises on the computer and answer questions there – it took at least a few hours. Then in the afternoon, after lunch, we had to go through various stations. Give a urine sample (complete privacy for that), we had to do a strength test and they tested the volume of our lungs with some device we had to breath into, they also measured and weighed us (only take off the shoes). The soldier who weighed me made fun of me being underweight, which was pretty embarrassing. Then I had a talk with a psychiatrist, who by the way was pretty rude. The exam continued the next day. We all had to wait in a big room with multiple exam rooms adjacent to it. Then, always one guy was ordered into each exam room. There, there were a doctor (a woman, not very friendly) and a recruit typing things into a computer. She asked me a lot of questions about my health and then told me to take off everything except my underpants. She explicitly mentioned to also take off my socks. Then she made me walk around the room, bend forward while she checked my spine, I had to lift my feet and she took a quick look, then she did the ascultation and afterwards she made me lie down on an exam table. There, she started palpating my belly, which made me laugh because I'm very ticklish. She told me to relax multiple times, but I just couldn't, which was a rather weird situation to me. She then lowered my underpants a little bit, but not enough to expose my genitals and she palpated this area. Again, I started laughing and she told me to stop. After that she had me stand up again and told the recruit what he had to type. Then she looked into her file again, and only after that she told me to get dressed and leave the room. Then, after a few hours of waiting, I was called into an office where some seemingly important military man told me I was postponed and I needed to redo the entire exam after two years. Thank god I had a good lawyer and knew an actual psychiatrist who could get me out of this by writing a serious complaint and threatening going to court. In the end, I was declared unfit for service.
Since then, I never had a physical exam again, except at the dentist, the eye doctor and my GP who vaccinated me and also froze a few warts on my feet, for which I obviously had to take off my socks.