When season 15 begins.
Vanguard Tokens are going the way of the dodo. Players logging in to Destiny 2 this week will be greeted by a warning; use your Vanguard tokens now or lose them forever. Vanguard tokens serve as the currency for Zavala in the tower and with season 15 they are going away forever.
Bungie recommends players redeem any leftover Vanguard tokens ASAP, as they have until August 24 to do so. Hopefully Zavala will receive rewards that are actually useful to Guardians with the new season.
MMO Fallout 