when do you stop being a master and become a mister
Master (form of address) Nancy Tuckerman of the Amy Vanderbilt Complete Book of Etiquette writes that in the USA, unlike the UK, a boy can be addressed as master only until age 12, then is addressed only by his name with no title until he turns 18, when he takes the title of Mr.,[3]:662 although it is not improper to use Mr. if he is slightly younger. Robert Hickey, deputy director of the Protocol School of Washington, states that "use of Master [as] an honorific when addressing boys is considered old fashioned outside of conservative circles."[4]
Master chief petty officer A fleet master chief petty officer (FLTCM) is a master chief who again has virtually the same responsibility as command master chiefs, but for larger fleet commands. There are four fleet master chief positions in the Navy:[4]