When it is not necessary to change, it is necessary not to change.
(Lucius Cary Falkland, 2nd Viscount (1610-1643), British statesman, soldier, patron. speech, Nov. 22, 1641, to the House of Commons. "A Speech Concerning Episcopacy," Discourses on the Infallibility of the Church of Rome (1660).)
Change your opinions, keep to your principles; change your leaves, keep intact your roots.
(Victor Hugo (1802-1885), French poet, novelist, playwright, essayist. Trans. by Lorenzo O'Rourke. "Thoughts," Postscriptum de ma vie, in Victor Hugo's Intellectual Autobiography, Funk and Wagnalls (1907).)