It's called Chekov's Gun/Chekov's skill, and it's a common storytelling device.This is really the solution to a lot of your problems in terms of writing. I've lost count of the times that some random BS from the begining of a season has had major plot importance later down the line in the shows I watch.
In a nutshell, minor details wouldn't have screentime spent on them unless they were going to be plot-relevant at some point.
It's not the same in games, where you can spend time on pretty much anything, but a movie or tv episode has a set runtime."If you say in the first chapter that there is a rifle hanging on the wall, in the second or third chapter it absolutely must go off. If it's not going to be fired, it shouldn't be hanging there."
-Anton Chekhov (From S. Shchukin, Memoirs. 1911.)
Even a book might have a page-limit.
Every minute on-screen is devoted to building something. Nothing that is shown is meaningless.
If a character is shown locking himself out of his house then picking the lock to get back in, then you can rest assured that the writers are letting you know that he knows how to pick locks, because it's going to be important at some point.
Likewise for if you find out that a character keeps a gun under his bed, or that a guy can juggle.