Replace all of those freaking Porter Moogle storage slips with ONE.
And make it a KI.
The reason for storage slips has to do with how stuff is stored in the database. Each object can have a maximum amount of data with it (including things like crafter signature), and the storage slips combine information for certain types of items into as compact a form as possible. They store the maximum possible number of items in the limited data area.
For instance, event gear isn't augmentable, so you either have it or you don't, and each item becomes ONE BIT in the storage slip data. REM gear has a bunch of different tiers of upgrades, but they follow just a few paths of trials. Since you should only ever have one of them, it could be, say, a four-bit or eight-bit number representing which version you have.
Notice how there's not a storage slip for Skirmish items? That's because they can have so many different augments.
Yeah, there's a lot of storage slips, but there's a reason there are so many, and that's because there's a bazllion items in the game. Think of each one of them as a sort of punched card, with each punch referring to a specific item or version of an item.
And I never even started using them. I was sad when the old-school event item storage NPCs stopped getting upgraded for new item types, but they probably ran out of whatever data space that used.