I have to keep all Vog weapons on my hunter. All crota weapons on my warlock and all other weapons on my titan. Only exception is fatebringer which I have as my main on each character. I do of course move weapons between characters but they must be put back before logging off. I keep all exotics in the vault (1 of each) except icebreaker and ghorn which I have one for each class. Any exotics that drop for me now get scrapped unless of course I need them. [This in itself will prove to be an issue as currently I have 19 exotics in my vault, my icebreakers and ghorns on my characters which means I am still missing 3 exotics - hawkmoon, mida and red death. If I get them it means I can't keep them all in my vault. This makes me sad] There are many others but I would be here all day :)