Yes, delete; no, save; no, I don't know. Either has benefits. Starting over from scratch often results in tighter focus, tighter writing, applying methods learned from first efforts. However, some redeemable passages might come in handy for rewriting. There's a hunch speaking behind the frustration. What is it? What is it trying to say? Structural or aesthetic hunch? Style, craft, or voice hunch? The four areas I find most struggling creative writers have difficulty with are SPICE development (setting, plot, idea, character, and setting), identifying and staying on task with a main dramatic complication, narrative point of view, specifically narrative distance and narrative voice, and building reader rapport.
"A writer . . . must not only have a story to tell but a story that he must tell. And, in order to do so, he must struggle to find a voice. Whether he works with or against the natural iambic meter of the English language, the writer must be in love with language, with the words themselves, the sound of the words on the page, the music they make in meaning. He must love them not so much in order to express the self as to discover a self, and, through it, his province, his territory, the territory of his story." --Lynn Freed, "Doing Time," in Harper's, July 2005, pp 65-72.
Prelude from an MA creative writing program assignment for a Seminar in Creative Writing Topics: Reading As Writers: Technique, Style, and Form
http://core.ecu.edu/engl/whisnantl/6865/ass1.htm
Spread the love of written word.