I think we must quote whenever we feel that the allusion is interesting or helpful or amusing.
“Life was very simple. My parents had come from the North of England, which is a fairly rugged, bleak, hard-working part of England, and so there was not the expectation of luxury.”
“Atlas was permitted the opinion that he was at liberty, if he wished, to drop the Earth and creep away; but this opinion was all that he was permitted.”