When do FF games start needing walkthroughs? (Specifically, IV and V need them?)

[Snap Jumper]

Final Fantasy IV - Everything can be re-explored for the most part. Some areas are. maybe just look online for missables and your good to play.

There's no way to reenter either of the towers nor the Giant of Babil. And there's a lot of good stuff you may not want to miss out on.