I'm having a hard time understanding some fundamental properties of our expanding universe. It seems reasonable that globally the size of the universe increases bc of the expansion. However the size of each causal patch/observable universe stays the same. Following this logic it would seem that the number of causal patches/causally connected regions increases with time - but that seems very debatable since causal patches refer to fixed points relative to which matter content moves away from. So what is true? Does the number of patches increase or stays constant in spite of the increase of the volume of space? Thank you.