What sorts of common things do you use Circuit Networks for?
So after 1500+ hours of Factorio/Space Age, I figure it's finally time to start a new game and learn about circuit networks (and train signals, but that's another headache for later). I imagined doing things like being able to automatically fix things (like when I hit a bottleneck from a full tank of light/heavy oil stopping all oil production).
New game from scratch, just started extracting oil.
Currently I'm still in baby steps, doing simple things just to learn (while watching tutorial videos), like "let's disable the inserter connected to this chest when there's 20 items in it".
Q1) I know there's so many possibilities, but wanted to know what sorts of basic things that you find really helpful to do with a Circuit Network? For those folks who feel circuit networks are a Must Have for Factorio play, what are the first things you end up doing with them?
Q2) Have you used circuits on space platforms/spaceships? What do you use them for?
Q3) How about on Gleba?
Again, I'm in baby steps, and looking ahead to exploring how circuit networks can help me down the line!