Many people believe that bagpipe tunes all sound the same.
   
“When you’ve heard one bagpipe tune, you’ve heard them both” was printed in the time travel novel From Time to Time (1995) by Jack Finney (1911-1995). “When you’ve heard one bagpipe song, you’ve heard them both” was printed in the Portland (ME) Press Herald on October 1, 1995. “Bagpipes droning is always good for dispersing a crowd. ‘If you’ve heard one bagpipe song, you’ve heard them both’” was posted on Twitter by 💧Gavin Scott on January 4, 2019. “Once you’ve heard one bagpipe tune, you’ve heard them both” was posted on Twitter by Robert Wilkinson on May 13, 2023.
 
           
Wikipedia: Jack Finney
Walter Braden “Jack” Finney (born John Finney; October 2, 1911 – November 14, 1995) was an American writer. His best-known works are science fiction and thrillers, including The Body Snatchers and Time and Again. The former was the basis for the 1956 film Invasion of the Body Snatchers and its remakes
         
Google Books
From Time to Time
By Jack Finney
New York, NY: Simon and Schuster
1995
Pg. 285
Fortunately he wasn’t too close to me — when you’ve heard one bagpipe tune you’ve heard them both — but the crowd listened quietly.
 
1 October 1995, Portland (ME) Press Herald, “The Greatest Escape Civilization Recedes Before the ‘Grandeur and Glory’ of Mount Katahdin and Baxter State Park by Roberta Scruggs, pg. 14D:
So when he mentioned he played the bagpipes (Irish ones, as befits his name and heritage) I thought I would lighten the mood a bit. I told him that by a happy chance I had just read a bagpipe joke.
 
“When you’ve heard one bagpipe song,” I said, “you’ve heard them both.”
 
I laughed. Even John snorted a little. Brendan just said, “Yeah, right.”
 
Google Groups: novell.community.chat
I’m lost with nowhere to went
.(JavaScript must be enabled to view this email address)
Jun 5, 2001, 3:28:53 PM
(...)
When you’ve heard one bagpipe tune you’ve heard them both.
-Jack Finney, “From Time to Time”
 
Twitter
Veronica
@SurrendrDorothy
When you’ve heard one bagpipe tune, you’ve heard them both.
Jack Finney
9:47 PM · May 23, 2009
     
Twitter       
💧Gavin Scott
@gavin_tweets
Bagpipes droning is always good for dispersing a crowd. “If you’ve heard one bagpipe song, you’ve heard them both.”
6:44 AM · Jan 4, 2019
   
Twitter
668: The Neighbor of the Beast
@668_Beast
My brother-in-law, leaning over to me at a funeral:  “Bagpipe songs. If you’ve heard one, you’ve heard them both.”
4:23 PM · May 16, 2019
 
Twitter
j.c.smith
@cliche_mist
“When you’ve heard one bagpipe tune, you’ve heard them both.” ~ Jack Finney (1911-1995)
12:43 AM · Jul 27, 2019
 
Twitter
Frankp
@CogitoErgoWtf
You will “appreciate” a dear friend of mine’s observation: “When you’ve heard one bagpipe song, you’ve heard them both.”
8:24 PM · Aug 31, 2019
 
Twitter
Frankp
@CogitoErgoWtf
I happen to love the sound of all of these,  but I am reminded of what a fellow I used to work with would say: “If you’ve heard one bagpipe song, you’ve heard them both.”
11:22 AM · Dec 11, 2022
 
Twitter
Robert Wilkinson
@robertwlk
Once you’ve heard one bagpipe tune, you’ve heard them both.
2:06 AM · May 13, 2023