After many Caminos, I have a rule of thumb: If I haven't seen a yellow arrow/marker within 15 minutes, I am contemplating going back to the last one I saw and proceed very carefully from there. But in general, it is hard to miss the direction on any Camino I have walked. Pay attention, that's all.
I once had to help a lady right outside the door of the municipal albergue in Burgos. She was shouting: "Where are the arrows!?" I told her to spread her legs and look down: Right beneath her, between her legs, there was a bronze scallop pointing the direction...
Edit: It is surprising, how many times I have silently asked for a sign, and shortly afterwards, a yellow arrow has popped up. The same goes for a place to sit down for a needed rest... The Camino provides...