“Experience is the best teacher” is a proverb that can be traced back to classical Rome. The French composer Hector Berlioz (1803-1869) wrote in a letter in November 1856:
 
“Le temps est un grand maître, dit-on; le malheur est qu’il soit un maître inhumain qui tue ses élèves.”
“Time is a great teacher, but unfortunately it kills all its pupils.”
 
The line can also be translated as “time is a great master.” The popularity of the line in English, however, is recent. “Time is a great teacher, but unfortunately it kills all its pupils.—Berlioz” is from a 1986 newspaper. The saying has appeared on many websites and in many books since the 1990s.
 
     
Wikiquote: Hector Berlioz
Louis Hector Berlioz (December 11, 1803 – March 8, 1869) was a French composer, conductor and music critic, widely seen as the greatest representative in music of the French Romantic school.
 
Sourced
Le temps est un grand maître, dit-on; le malheur est qu’il soit un maître inhumain qui tue ses élèves.
Time is a great teacher, but unfortunately it kills all its pupils.
. Letter written in November 1856, published in Pierre Citron (ed.) Correspondance générale (Paris: Flammarion, 1989) vol. 5, p. 390; Paul Davies About Time: Einstein’s Unfinished Revolution (New York: Simon & Schuster, 1996) p. 214.
 
The Phrase Finder
EXPERIENCE IS THE BEST TEACHER - “The great Roman leader Julius Caesar recorded the earliest known version of this proverb, ‘Experience is the teacher of all things,’ in ‘De Bello Civili’ (c. 52 B.C.). Over a century later, the Roman author Pliny the Elder in ‘Naturalis Historia’ (A.D. 77) wrote, ‘Experience is the most efficient teacher of all things,’ and the Roman historian Tacitus said simply, ‘Experience teaches,’ in his ‘Histories’ (c. 209). The earliest English rendering appeared in 1539 as ‘Experience is mother of prudence,’ which was included in Richard Taverner’s ‘Proverbes or Adagies.’.the exact wording, ‘Experience is the best teacher,’ appeared in the ‘Widow Bedott Papers’ by Frances M. Whitcher.”
 
Google Books
Life and Times of Frederick Douglass
By Frederick Douglass
Hartford, CT: Park Publishing Co.
1882
Pg. 487:
Some one has said that “experience is the best teacher.”
   
11 June 1951, Springfield (MA) Union, “On Broadway” by Walter Winchell, pg. 11, col. 7:
HISTORY IS A GREAT teacher. Unfortunately, it has never been able to impress enough students.
 
10 December 1982, The Sun (Baltimore, MD), “For novice marathoners, a few tips” by Susan Reimer, pg. D3:
Vernon Law, a former Pittsburgh Pirate pitcher, used to say that experience is a great teacher. Unfortunately, he said, it gives the tests first and the lessons after.
 
1 January 1986, The Times (Trenton, NJ), “Of time and New Year’s,” pg. A12, col. 1:
Time is a great teacher, but unfortunately it kills all its pupils.
—Berlioz
 
Google Books
The Unofficial Gardener’s Handbook
By Shelley Goldbloom
New York, NY: Plume
1992
Pg. 108:
They say that time is the best teacher. Unfortunately it kills all of its pupils.
   
28 February 1997, Orlando (FL) Sentinel, Lake Sentinel, pg. 1:
Time is the best teacher; unfortunately it kills all its students!
 
Google Books
Boomerang Joy: Joy That Goes Around, Comes Around
By Barbara Johnson
Grand Rapids, MI: Zondervan
1998
Pg. 143:
Time is the best teacher; unfortunately, it kills all its students.
   
WRAL.com (Raleigh-Durham-Fayetteville, NC)
Posted: October 23, 1998
Turn the Clock Back, It’s No Longer Daylight-Saving Time
(...)
A great musician, Hector Berlioz once said; “time is a great teacher. Unfortunately it kills all its students” - remember to set back your clock Saturday night.
 
Google Books
Wardlife:
The apprenticeship of a young writer as a hospital clerk
By Andrew Steinmetz
Montreál, Québec: Véhicule Press
1999
Pg. 165:
My grandfather used to say: Life is a great teacher but it kills all its students. He told me he read that somewhere — the human condition, elusive as intellectual property rights.
 
Google Books
Trading Chaos:
Maximize profits with proven technical techniques
By Justine Gregory-Williams and Bill Williams
Hoboken, NJ: J. Wiley
2004
Pg. 30:
As the composer Hector Berlioz commented, “Time is the great teacher, but unfortunately it kills all its students.”