What’s in a contact anyway?

I noticed something peculiar a few weeks back. A colleague at office had not saved the number of a third-party contractor. A fairly mundane thing. But why would you do that? This was a person she had to contact on a regular basis, for months, if not years, and she did not save his number. My curiosity only resulted in a quick retort about her being good at remembering phone numbers. Too quick to…