How each upgrade works
| Structure | Material | Bonus rule |
|---|---|---|
| Fountain of Life | Water Essence and required Prosperity | Level bonuses stack |
| Reservoir | Water Essence and required Fountain level | Worker count follows level |
| Ordinary decoration | Unplaced level-one copies of the same decoration | Current level of active copies only |
| Island Wonder | Its blueprint | Owned Wonder bonus works without display |
Type Limits and storage
- Only placed ordinary decorations count. Stored copies add no bonus or Prosperity.
- Each decoration has its own Type Limit; the highest-level placed copies take priority up to that limit.
- A Type Limit of zero means the decoration contributes no stat bonus or Prosperity.
- An upgrade consumes spare level-one copies from the Island Storehouse. The total-copy figure includes the copy being upgraded.
- Dismantling an upgraded ordinary decoration returns the level-one copies used. Fountain and Reservoir rules differ.
Decorations accepting general components
| Decoration | Component support |
|---|---|
| Braveshrine | Check component conversion in its upgrade panel |
| Bustling Tavern | Check component conversion in its upgrade panel |
| Observation Deck | Check component conversion in its upgrade panel |
| Speaker Hall | Check component conversion in its upgrade panel |
| Floating Market | Check component conversion in its upgrade panel |
| Amphitheater | Check component conversion in its upgrade panel |
| Merchant Caravan | Check component conversion in its upgrade panel |
| New Year Greeting | Check component conversion in its upgrade panel |
| Journey of the Heart | Check component conversion in its upgrade panel |
| Starstation | Check component conversion in its upgrade panel |
| Eggchanted | Check component conversion in its upgrade panel |
| Jade Jubilation | Check component conversion in its upgrade panel |
| Grizzly Statue | Check component conversion in its upgrade panel |
| Cheesy Perfection | Check component conversion in its upgrade panel |
| Lantern Garden | Check component conversion in its upgrade panel |
| Wicked Hut | Check component conversion in its upgrade panel |
| Autumn Canvas | Check component conversion in its upgrade panel |
| Winter Rollercoaster | Check component conversion in its upgrade panel |
| Lakeside Dream | Check component conversion in its upgrade panel |
| Ritual Altar | Check component conversion in its upgrade panel |
| Dinosaur Fort | Check component conversion in its upgrade panel |
| Pro Ball Trainer | Check component conversion in its upgrade panel |
| Mini Crucible | Check component conversion in its upgrade panel |
| Dream Sailing | Check component conversion in its upgrade panel |
Choose the next upgrade
Compare the gain at the next level with the number of copies it consumes. A bonus you use every day can matter more than a bigger Prosperity number. If the next Fountain level is blocked only by Prosperity, compare eligible placed decorations rather than buying excess copies of a Type-Limit-one decoration.