The Staircase Implementation - The Big Theory (Season 3, Episode 22) - Apple TV.
The apartment is officially located at 2311 North Los Robles Ave. — a fictional address, since the street ends in the 2200 block, ing to Blake. But fans have theorized that it's based on the Brookmore Apartments, with fans noting that the inside looks exactly like the show.
Fans of the hit sitcom will know that Sheldon (Jim Parsons) had a first roommate, Sebastian (Oscar nominee Steven Yeun), prior to Leonard (Johnny Galecki) moving in.
Sheldon and Leonard live together out of convenience not for financial reasons. Sheldon has said in the past that he wouldn't have a roommate if he could afford the rent. Penny on the other hand who lives alone on a smaller wage, is seen always struggling to get by, living paycheck to paycheck.
My take is that at the time when he was interviewing for a roommate, he was just freshly starting out at his job so the rent was too expensive for him to afford alone, but as his work in the university gradually secured him a steady income years later, he earned more than enough to live alone, but he simply chose not ...
It was the one titled The Staircase Implementation. He moved in with Sheldon in 2003.
It dictates what Leonard has to eat each day of the week, what TV shows he is allowed to watch, whether he has a girlfriend stay over, that he has to drive Sheldon everywhere he wishes to go, whenever he wishes. It even dictates when Leonard is allowed to use the bathroom.
Roommate agreement with apartment flag logo. The Roommate Agreement was written by Sheldon and was signed by Leonard when they first became roommates. These events were shown during a flashback in "The Staircase Implementation".