Forbidden Materia

[Betelgeuzah]

That means that if you fail on the 2nd attachment you are basically throwing away 3 whole items, and not just 3 made items but 3 items you had to put significant effort to grind spiritbond.

You buy them off people who are looking to make a quick buck and aren't interested in attaching multiple materia.

Doing this time-consuming process by yourself when people that don't see much value in keeping theirs want to get rid of them for some gil would be quite a dumb move. But to each his own.