Sifu · Shrine upgrade
Structure Reserve
Structure Reserve increases maximum structure, giving you more room to guard before your structure breaks. IGN says the upgrade is locked once you pass age 60; EIP describes it as an age-gated option for players learning to survive longer.
How it works
It is a Dragon Shrine upgrade and can be chosen only at age 60 or younger. Shrine visits allow one additional upgrade per visit, subject to requirements. The supplied evidence does not state its XP or score cost.
When it helps
Consider it while within its age limit if you want more guard capacity.
Read the supporting references
The Best Shrine Upgrades and Skills for Beginners - Sifu - EIP Gaming How to Use Shrines - Sifu Guide - IGN
Check the edition and source version for patch-specific details. Guide methodology.