Who does the PREMIUM PLUS Repair Cupboard discount apply to? Does it work if I'm authorized in a friend's cupboard?

The PREMIUM PLUS upkeep discount belongs to the Repair Cupboard, and it's decided by one player only: whoever placed that cupboard.

How it works. The game checks whether the cupboard's owner has PREMIUM PLUS. If they do, that cupboard's upkeep costs 50% less. Nothing else is taken into account.

Being authorized doesn't count. It makes no difference how many players are authorized in the cupboard, or how many of them have PREMIUM PLUS. Authorization gives you building rights, not the discount. If the owner has no PREMIUM PLUS, the cupboard pays full price even when everyone authorized in it is subscribed.

So for a shared base: the discount applies only if the player who placed the cupboard has PREMIUM PLUS. If someone else in the group has it instead, it does nothing for that base — they would have to be the one placing the cupboard.

It updates on its own. The check runs continuously, so you never need to replace the cupboard: buy PREMIUM PLUS and the discount starts applying to a cupboard you already own; let it expire and the cost returns to normal.

It doesn't stack with the clan perk. If your clan also reduces upkeep, the game applies whichever of the two is better — not both together.

You can tell it's active by the subscription icon on the cupboard screen, next to the upkeep cost.