No different than the auto-dial feature on the phone, after a couple of years it’s fun to watch people sitting there going “What the hell is my wife’s cell phone number again?” when it’s gone.
I have some of them written down in my wallet, but no, I don't even attempt to memorize them anymore. I don't even know my own cell number. I have to look it up every time someone asks.
But I do remember numbers from 30 or more years ago that I came to memorize back then by calling them often.