A friend of mine sent me a text last month. “Hope you’re doing well,” he said. “Any time for a call, just to catch up?” It’s always nice when a friend reaches out  — this friend is particularly diligent at staying in touch — so we set a time for a chat the next day.

It was only later, after the friendly call, that I glanced at his contact card on my phone. Our previous calls were listed, along with the date of each, and I noticed that he and I talk every five weeks. Not every five weeks or so, but every five weeks to the day. Each time preceded by a text.