Casting Hex requires a verbal, somatic, and material component. For the duration (1/8/24 hours), if something dies while hexed, I can use a bonus action to apply it to a different creature.
Does reapplying Hex have a verbal, somatic, or material component?
The context being whether or not it would be obvious that I was reapplying the spell to another target or if I would have to try and hide it. I could, in theory, kill something I've hexed and then several hours later sneakily apply the spells' ability disadvantage to a creature and he would never know (or his friends would never know).