Advice on Adding Material to Items

[Niwashi]

as i understand it you can convert anything that is bonded to you to material, and it will have certain properties. how do you find out what properties it will have before you convert it?

You don't. The specific materia that it converts to isn't determined until you convert it. However, there is a tendency for DoW armour and weapons to convert to materia with DoW-relevant buffs, DoM armour and weapons to convert to materia with DoM-relevant buffs, and so on with DoH or DoL items.

And how long do you have to wear it before it is bonded? sadly i sold some early stuff that was bonded as i didnt know then about this.

I haven't paid enough attention to it to tell you exactly how long it takes, but each piece of gear will show its SpiritBond as a percentage. When that percentage reaches 100%, it's possible to convert it. So if you reach the point where you can upgrade a piece of gear, but it's at 97%, you may want to keep it equipped a little longer to finish off the spiritbond first. On the other hand, if you have better gear to replace something that's only at 45%, go ahead and replace it and just vendor the old gear, it's not worth keeping poor gear equipped that much longer.