I was required to buy one at the beginning of med school. I hardly ever use it now. I definitely needed it during first and second year, though. During our Introduction to Clinical Medicine course, we had to do complete exams every week on real patients at the hospital, and not every ward had an oto-ophthalmoscope available.
Since then, I haven't used it. It sits on my shelf collecting dust now because there is always one in the admitting area or clinic room. Plus, now if I absolutely need one on the floor and there isn't one available, I know where to go to get one.