Note to Hamlet, 4.7.78-79: "for youth no less becomes / The light and careless livery that it wears"

for youth no less becomes / The light and careless livery that it wears: youth looks becoming in the light and carefree clothes that it wears.  —Literally, a "livery" is a uniform or distinctive clothing worn by members of a family, or servants in a household; here the word is being used as a metaphor for youthful values and interests.