John Henry Newman (1801-1890), also known as Cardinal Newman, wrote in An Essay on the Development of Christian Doctrine (1845):
 
“In a higher world it is otherwise; but here below to live is to change, and to be perfect is to have changed often.”
 
Newman’s words have been repeated by many, including Winston Churchill (1874-1965), who said in the House of Commons in 1925:
 
“There is nothing wrong with change, if it is in the right direction. To improve is to change, so to be perfect is to have changed often.”
 
Churchill’s version is often cited, without acknowledgment of Newman’s original words. The saying has been printed on several posters, with “To improve is to change; to be perfect is to change often” the popular form of Churchill’s quotation.
 
     
Wikiquote: John Henry Newman
Blessed John Henry Cardinal Newman (21 February 1801 – 11 August 1890) was an English convert to Catholicism, later made a cardinal.
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An Essay on the Development of Christian Doctrine (1845)
In a higher world it is otherwise, but here below to live is to change, and to be perfect is to have changed often.
. Chapter 1, Section 1, Part 7.
 
Wikiquote: Winston Churchill
Sir Winston Leonard Spencer Churchill KG OM CH TD FRS PC (Can) (November 30 1874 – January 24 1965) was a British politician and statesman, best known for his leadership of the United Kingdom during World War II. He was Prime Minister of the UK from 1940 to 1945 and again from 1951 to 1955. He received the Nobel Prize for Literature in 1953.
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To improve is to change, so to be perfect is to have changed often.
. Winston Churchill, “His complete speeches, 1897-1963”, edited by Robert Rhodes James, Chelsea House ed., vol. 4 (1922-1928), p. 3706. Lors d’un débat avec Philipp Snowden, chancelier de l’Echiquier, à propos des droits de douane sur la soie.
. Often misquoted as: To improve is to change, to be perfect is to change often.
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But now let me return to my theme of the many changes that have taken place since I was last here. There is a jocular saying: ‘To improve is to change; to be perfect is to have changed often.’ I had to use that once or twice in my long career.
. Address to a joint session of Congress, Washington, D.C., January 17, 1952 “We Must Not Lose Hope”, in The Great Republic : A History of America (2000), Churchill, Random House, p. 399 ISBN 0375764407
   
Google Books
An Essay on the Development of Christian Doctrine
By John Henry Newman
London: James Toovey
1845
Pg. 89:
In a higher world it is otherwise; but here below to live is to change, and to be perfect is to have changed often.
 
Google Books
December 1877, The Contemporary Review, pg. 210:
Very good is this about Peel, and the subsequent touch about Mr. Gladstone is highly amusing:—
 
“The following sentence would form a good motto for a future life of Peel:—‘In a higher world it is otherwise, but here below to live is to change, and to be perfect is to have changed often.’”
 
22 September 1932, National Labor Tribune (Pittsburgh, PA), pg. 4, col. 5:
Progress.
To improve is to change. To be perfect is to have changed often.—Winston Churchill.
 
Google Books
Churchill by Himself:
The Definitive Collection of Quotations
By Richard Langworth
New York, NY: PublicAffairs
2008
Pg. 13:
Change
There is nothing wrong with change, if it is in the right direction. To improve is to change, so to be perfect is to have changed often.
1925, 23 JUNE. (EPHESIAN, 3RD ED., 1936, 288.)
Exchange in the House of Commons with Philip Snowden when Churchill defended his first budget.
 
Twitter
Winston Churchill
‏@churchillqu0tes
To improve is to change; to be perfect is to change often. http://pandaquotes.chucklesnetwork.com/quotes/4485/to-improve-is-to-change-to-be-perfect-is-to-change-often/?utm_campaign=auto_social&utm_source=twitter&utm_medium=%40churchillqu0tes … #winstonchurchill #churchill #quote #quotes
3:59 AM - 20 Jun 2015