It always works for me, and I don't even mind at all when people do the same. If I don't know you, your surname is either the church, school, bank, or wherever we met. Nobody should vex. Lmao. I would only upgrade your name from Dayo 300L MTE when we become closer, even though you were two years my senior when I was in 100L, and I graduated two years ago.
RE: The very systematic way I saved phone numbers in school. e.g Anu ACC'23