You live only once The logician would argue, You only live once should be rewritten as You live only once, with only next to the thing it qualifies, once. The logician would be unbearably pedantic, but there is a grain of good taste in the pedantry. Writing is often clearer and more elegant when a writer pushes an only or a not next to the thing that it quantifies. In 1962 John F. Kennedy declared, “We choose to go to the moon not because it is easy but because it is hard.” That sounds a lot classier than “We don’t choose to go to the moon because it is easy but because it is hard." Steven Pinker, The Sense of Style grammar
Structural parallelism If the new phrase has the same structure as the preceding one, its words can be slotted into the waiting tree, and the reader will absorb it effortlessly. The pattern is called structural parallelism, and it is one of the oldest tricks in the book for elegant (and often stirring) prose. “He maketh me to lie down in green pastures; he leadeth me beside the still waters.” Steven Pinker, The Sense of Style The principle of parallel construction