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
The principle of parallel construction This principle, that of parallel construction, requires that expressions similar in content and function be outwardly similar. Blessed are the poor in spirit; for theirs in the kingdom of Heaven. Blessed are they that mourn; for they shall be comforted. Blessed are the meek; for they shall inherit the earth. William Strunk Jr. & E.B. White, The Elements of Style Structural parallelism form