to your dying day
for the rest of your life. 1967 George Mackay Brown A Calendar of Love This one always was and ever will be to his dying day a garrulous long-winded old man.
dying day, to one's
For the rest of one’s life. The English poet George Sandys used the expression as long ago as 1599: “To have a sight of her sometime before their dying-dayes.” The cliché usually appears in a somewhat melodramatic or hyperbolic context, such as “I’ll never forget this garden, not to my dying day.”