When something happens or continues for days on end, it means it’s continuing without any sign of stopping. It’s an expression with a fair bit of history and reaches back several centuries.
In 1949, the expression was used in “The Royal Engineers Journal” where the following can be found with regards to the post D-Day invasion of northern France.
Often frozen and wet through by night, they proceeded to march and fight at top speed for days on end. This was the 6th Airborne, with wings on its feet as well as its shoulders, and a spirit which said, ‘Bash on regardless.’
Jack London (1876 – 1916) wrote and published “Adventure” in 1911. In Chapter XVII entitled, “Making The Books Come True” the following passage is found:
The steamer from Sydney, the Kammambo, broke the quietude of Berande for an hour, while landing mail, supplies, and the trees and seeds Joan had ordered. The Minerva, bound for Cape Marsh, brought the two cows from Nogi. And the Apostle, hurrying back to Tulagi to connect with the Sydney steamer, sent a boat ashore with the orange and lime trees from Ulava. And these several weeks marked a period of perfect weather. There were days on end when sleek calms ruled the breathless sea, and days when vagrant wisps of air fanned for several hours from one direction or another. The land-breezes at night alone proved regular, and it was at night that the occasional cutters and ketches slipped by, too eager to take advantage of the light winds to drop anchor for an hour.
In Sir Arthur Conan Doyle‘s book “A Study In Scarlet” which was published in 1887, the following is found in Part I, Chapter 1 where Dr. Watson, late of the Army Medical Department, reminiscences about Sherlock Holmes in this fashion:
Sherlock Holmes seemed delighted at the idea of sharing his rooms with me. “I have my eye on a suite in Baker Street,” he said, “which would suit us down to the ground. You don’t mind the smell of strong tobacco, I hope?”
“I always smoke `ship’s’ myself,” I answered.
“That’s good enough. I generally have chemicals about, and occasionally do experiments. Would that annoy you?”
“By no means.”
“Let me see — what are my other shortcomings. I get in the dumps at times, and don’t open my mouth for days on end. You must not think I am sulky when I do that. Just let me alone, and I’ll soon be right. What have you to confess now? It’s just as well for two fellows to know the worst of one another before they begin to live together.”
I laughed at this cross-examination. “I keep a bull pup,” I said, “and I object to rows because my nerves are shaken, and I get up at all sorts of ungodly hours, and I am extremely lazy. I have another set of vices when I’m well, but those are the principal ones at present.”
Various books, documents, stories, newspaper accounts et al make use of the expression days on end. Idiomation’s research unearthed that the word end comes from the Old English word ende which is from the Old Norse word endir which means “the opposite side” or “boundary.” The original sense of the word means “outermost part” and dates back to the 900s however this sense is obsolete except in phrases such as days on end.
According to the American Heritage Dictionary of Idioms, the expression dates back to some time in the 1300s.
Historically Speaking 