Luck was believed to be, according to the Eleventh Doctor, "an intangible force that helps [gamblers] win or lose". He deduced that Joe Buchanan had faith in luck from his dice cufflinks and horseshoe chain. The Minotaur fed on Joe's faith in luck, killing him. (TV: The God Complex [+]Toby Whithouse, Doctor Who series 6 (BBC One, 2011).) Luck was always fickle. (COMIC: The Greatest Gamble [+]John Peel, DWM backup comic stories (Marvel Comics, 1981). Page 40.)
"Jinxing" was when someone said something similar to "what could possibly go wrong". The Doctor was known to jinx himself with such statements, and immediately regret it. (TV: Midnight [+]Russell T Davies, Doctor Who series 4 (BBC One, 2008)., The Doctor, the Widow and the Wardrobe [+]Steven Moffat, Doctor Who Christmas Special 2011 (BBC One, 2011)., Time Heist [+]Steve Thompson, Doctor Who series 8 (BBC One, 2014)., In the Forest of the Night [+]Frank Cottrell-Boyce, Doctor Who series 8 (BBC One, 2014).)
The Seventh Doctor believed that luck was merely a "reductive misrepresentation of statistical prediction". (AUDIO: Dark Universe [+]Guy Adams, Main Range (Big Finish Productions, 2020).)
Bob Kreesus used a luck machine, which he had won gambling, on the thirteenth moon of the thirteenth planet in the Thirteenth Galaxy, in order to extract the good fortune of others, and make himself lucky. Unaware of Kresus' tampering, the Triskaidekaphobes believed themselves to be the unluckiest people in the galaxy, and feared the number 13 above all else.
When the Tenth Doctor and Rose Tyler visited on Friday 13 January 1213, they were struck by lightning, and rained on by cats. In the end, the Doctor defeated Bob Kreesus by destroying his machine. Having lost his luck, Kreesus slipped on a banana peel and fell off a cliff. (COMIC: Triskaidekaphobia [+]Alan Barnes, DWA comic stories (BBC Magazines, 2006).)
A week after the Slitheen's failed attempt to plunge Earth into a nuclear war on 6-7 March 2006, Mickey Smith (TV: Aliens of London [+]Russell T Davies, Doctor Who series 1 (BBC One, 2005)., World War Three [+]Russell T Davies, Doctor Who series 1 (BBC One, 2005)., etc.) conducted an interview with Henry Van Statten. Van Statten told Mickey, that not unlike "daytrippers in the park", aliens that visited Earth sometimes scraps behind, and sometimes, things more interesting. And by his reckoning, times like that is when people like himself and Mickey got lucky. (PROSE: Henry Van Statten [+]BBC webteam, Who is Doctor Who? (BBC, 2005).)
In 3005, luck could be used as a currency in Space Vegas. (PROSE: Time Traveller's Diary)
During his game of cards against the Celestial Toymaker in the Toyroom, Gaylord Lefevre's luck began to sour, so he attempted to cheat against the Toymaker to "even the score". (COMIC: The Greatest Gamble [+]John Peel, DWM backup comic stories (Marvel Comics, 1981). Page 40.)
The Fifteenth Doctor described the memory TARDIS as being held together by hopes and wishes and luck. (TV: Empire of Death [+]Russell T Davies, Doctor Who series 14 (BBC One and Disney+, 2024).)