Gotta catch em all... Final fantasy style
Currently I'm cruising through Final Fantasy 7 with no guide; a loose cannon if you will.
What vastly important materia, weapons, or items do I not have the opportunity to go back and get if I miss it the first time?
Solution 1:
There's just too many things in ff7 to list that are missable (with many that are permanently missable) without a guide.
However, there is a nice missable items guide available if you choose to take a look.