I never wore a watch before my mission. I never felt like I needed one. I would use the clocks around my house, around my high school, on my car dashboard. If I went to a meeting or athletic training I didn't check the time throughout; it was over when it was over.
But my Grandpa Chuckles insisted that I needed a watch as a missionary. Of course, he was right. Having never been a missionary, I had no idea.