Placeholder buttons

With the inventory system you can create buttons with placeholders to check if the player has a certain value or not. So you can do this with zAuctionHouse:

Check the number of expired items

Using the placeholder %zauctionhouse_expired_item% you can get the number of items that have expired for the player. So you can create a button like this:

expireItems:
  type: INVENTORY
  slot: 45
  isPermanent: true
  inventory: "expire"
  placeHolder: "%zauctionhouse_expired_item%"
  value: 1
  action: SUPERIOR_OR_EQUAL
  item:
    material: CHEST
    name: "&fExpire items"
    lore:
      - "&f» &7You have &b%zauctionhouse_expired_item% &7expired items"
  else:
    slot: 45
    isPermanent: true
    type: NONE
    item:
     material: CHEST
     name: "&fExpire items"
     lore:
       - "&f» &7You have no pending items."

You will therefore have a check of greater or equal on the number obtained with the placeholder. For example, if the player has 5 expired items, there will be 5 > 1 then the button will be displayed normally. But if the player with 0 items expired, there will be 0 > 1 and the button in the else will be displayed.