It is 'customary' to hold the door open for someone who is entering a building behind you.
He did the work with his 'customary' efficiency.
She dressed in her 'customary' fashion.
(..) my beloved husband." Jem says this watch is gonna belong to him someday. - That's right. - Why? Well, it's customary for the boy to have his father's watch. What are you gonna give me? Well... I don't know that I have much else ofvalue that belongs to me. (..)1962 To Kill a Mockingbird