Letters 18.9

Even Epicurus, the teacher of pleasure, used to observe stated intervals, during which he satisfied his hunger in niggardly fashion; he wished to see whether he thereby fell short of full and complete happiness, and, if so, by what amount he fell short, and whether this amount was worth purchasing at the price of great effort. At any rate, he makes such a statement in the well known letter written to Polyaenus in the archonship of Charinus. Indeed, he boasts that he himself lived on less than a penny, but that Metrodorus, whose progress was not yet so great, needed a whole penny.

Seneca, Letters to Lucilius 18.9, translated by Richard Mott Gummere