"You're Getting to Be a Habit with Me" was written by Harry Warren in 1932, with lyrics by Al Dubin. It appears in the 1933 musical 42nd Street, and is sung by Bebe Daniels:
The song was inspired by one of the women working at the Warner Brothers studio, who when asked why she was still dating a certain man, said that he was getting to be a habit with her (source). So I suppose Warren or Dubin were within earshot.
Here are Frankie Avalon and Vikki Carr doing a respectable job of it on a 1965 episode of the short-lived sitcom The Bing Crosby Show:
Frankie is clearly channeling another version, by another Frankie, my favorite recording of "You're Getting to Be a Habit with Me," the one on Sinatra's 1956 classic album, Songs for Swingin' Lovers!.
This is one of those fantastic Sinatra/Nelson Riddle collaborations. I just love Riddle's cool, breezy arrangement, with its lush strings, vibes, those "Riddle flutes," and the playing of trumpeter Harry "Sweets" Edison. I've read somewhere Sinatra mandated that Edison should have his own microphone during the recording of Songs for Swingin' Lovers!, and it's easy to hear why on tracks such as this one. Longtime fans would have a hard time imagining many of Sinatra's recordings without Edison's playing.