"Words by which I live" started out as "Words to live by" but this former English teacher, former homeschooler, and current journalist couldn't bear to have a preposition at the end of the sentence. I believe Mark Twain said something to the effect of "A preposition at the end of a sentence is something up with which I will not put." Ah, cumbersome, but lovely to my ears. Of course, after a few glasses of wine, don't be surprised if "ain't" or a drawling curse comes out of my cabernet mouth.
Cheers and love,