Semper sometimes

A marine reservist

Often called "Semper sometimes". This is funny because Semper fidelis means "always faithful". Due to the nature of a reservist, they are the equivalent of part time workers in what is known as the Marine Corps. Therefore they are not "always faithful" which leads to them to only being faithful "sometimes". They are also called "weekend warriors" or "part timers" and are often the object of ridicule in jokes around real Marines

"John went the reservist route because he couldn't handle being a full time marine. Talk about Semper sometimes"