Die with your boots on
To "Die with your boots on" is an idiom referring to dying while fighting or to die while actively occupied/employed/working or in the middle of some action. A person who dies with their boots on keeps working to the end, as in "He’ll never quit—he’ll die with his boots on." The implication here is that they die while living their life as usual, and not of old age and being bedridden with illness, infirmity, etc. Origin
The "Die with your boots on" idiom originates from frontier towns in the 19th-century American West. Some sources (e.g., American Heritage Dictionary of Idioms) say that the phrase probably originally alluded to soldiers who died on active duty. The Oxford Dictionary of Idioms says: "Die with your boots on was apparently first used in the late 19th century of deaths of cowboys and others in the American West who were killed in gun battles or hanged." Cassell's Dictionary of Slang adds that from the late 17th century until the early 19th century the expression meant "to be hanged," and from the mid 17th century until the mid 19th century "Die in one's shoes" meant the same thing. See also
Boothill
Iron Maiden

In popular culture
They Died With Their Boots On, a 1941 Western film about General George Armstrong Custer
"Die with Your Boots On," a song from Iron Maiden's 1983 album Piece of Mind
"Dying with Your Boots On," a song from Scarface's 1993 album The World Is Yours
"Die with Your Boots On," a song by Toby Keith
"Play a Train Song," a song from Robert Earl Keen's 2011 album Ready For Confetti
Referenced in the lyrics to Genesis' song "Ballad of Big," from their 1978 album ...And Then There Were Three.... ("...and he died like all good cowboys, with his boots on, next to his men.") References

English-language idioms