I shaved my head when I started thinning. If I try to grow it back now, I might be a little thicker than Patrick Stewart. It wasn't obvious that I was losing my hair, even to me, really. It just wasn't quite as thick as it used to be. I had already shaved my head once when my mom was going through chemo and liked the look. So, when I finished grad school and was picking up my life and moving, the time was right. All my new co-workers and students had never seen me before so I could go completely bald and be the bald professor right from the start.
To be honest, while some days I don't feeling like razoring my head I don't miss my hair at all. I hated the color, I hated the texture, and I hated the stupid little wave it would get if it was too long. My head gets cold a lot more than it used to now but that's what hats are for. Good riddance, hair.