I've played a LOT of Factorio, but never really progressed beyond spaghetti phase

My question is: When you make a main bus - let's say left to right (eastwards), that kind of locks you into expanding ever westwards in search of more resources, doesn't it? Because if I run out of iron, and I need to feed a lot of into into the main bus, it's a lot easier if that iron comes from a source to the west, than a source far to the east. Thoughts?