Eschatēn

Οὐκ ἔστι τὴν ἐνεστηκυῖαν ἡμέραν καλῶς βιῶναι μὴ προθέμενον αὐτὴν ὡς ἐσχάτην.
(Musonius Rufus, fr. 22)

It is not possible to live well today unless one thinks of it as his last. (tr. Cora E. Lutz)