QUESTION
Should I buy a 65-inch TV if I sit 7 feet away?
Yes — a 65-inch TV is a reasonable choice if you sit 7 feet away, especially for 4K movies, sports, and gaming. It will feel fairly immersive, but not unusually oversized for most people.
At 7 feet, you are about 84 inches from the screen. For a 65-inch 16:9 TV, that gives a cinematic viewing angle of roughly the high-30-degree range, which is close to what many home-theater guidelines consider immersive. A 55-inch TV would feel more moderate and less dominant in the room, while a 75-inch TV would be noticeably more theater-like and may feel large for casual TV viewing at that distance.
My practical recommendation: choose 65 inches if you want an immersive modern 4K setup; choose 55 inches if you prefer a more relaxed, traditional TV size or watch lots of lower-quality cable/news; consider 75 inches only if you know you like a very big-screen feel.