I have sky and haven't really cracked into it once I found out how damn big this series was and I can see myself getting hooked on it pretty easily.You def should take breaks and take your time.
You pretty much can take a break in between any game in this series outside of after Sky FC, CS 1 or CS 3.
Sky 3rd, Azure and Reverie are sequels where I would recommend using as a break point after finishing rather then their predecessor but not a big deal.