I'm using an online calendar for the first time this semester and so far it's made scheduling a lot easier. My previous method mostly involved writing things down on bits of paper on my desk and going on the assumption that things I forgot about might not be that important.
This new calendar use, in addition to helping me remember things, lets me say "uh... let me check my schedule" whenever an event is brought up. I imagine it's a taste of professional life. On the other hand, there's probably nothing professional about interpreting a day with no calendar appointments as a day to do nothing.