Vault

The Vault is a machine located in the Tower where Guardians can store their excess gear.

Destiny 1
Every player's character has a Vault, where they can store items, namely up to 20 armor pieces, 20 weapons, and 20 general items (shaders, emblems, ships, Sparrows, etc.). The space was upgraded to 24 armor pieces, 36 weapons, and 24 general items in a future update, albeit at the expense of the comparison feature on the Xbox 360 and Playstation 3 versions.

Destiny 2
The Vault in Destiny 2 at first featured 300 slots for any type of item or gear, instead of fixed areas for armor, weapons and general items. It was upgraded to 500 slots with Update 2.0, which went live the week before the release of the Forsaken expansion. With the release of Season of the Haunted, vault space was increased to 600 slots.