In a 2019 interview with Filmmaker Magazine, Marshall Curry detailed key aspects of the production and storytelling: "It was a production challenge to find two apartments that faced each other. I knew if we tried to cheat it, the audience would feel the falseness. So I looked and looked, and in the end we shot in a very generous friends' apartment, and their neighbors also said okay...
The passage of time is an important part of the story - how Alli's obsession with the neighbors develops, and how the neighbors' lives change over the course of 18 months. That's tricky to squeeze into a film that's not even 20 minutes long. So we had to build in clues that communicated the passage of time - weather changing, holiday decorations, infant appearing and growing, etc. It's always a delicate balance between being too obvious and on-the-nose with those clues and being so subtle that people miss it altogether. When I was editing I would show people cuts and ask them at the end how much time they felt had passed. I'd add a few more clues or take a few away until I settled specific shots and specific durations in the final cut."