I have to keep all my materials and consumables (outside of synths, basic upgrade materials and glimmer drop items) on my main character. Can't have a single mote on my other 2. Plus all the base weapons stay on the same characters unless I want to use something specific. All my exotic weapons stay in the vault, so I have only 4 spaces for anything else. I can't separate them onto the characters, and only pull out the ones I want out for the time being