Recommended levels (least important first)

Radar / Warehouse / Trading Center: LV.17 This article lists side buildings and a "good enough" level for each group. The goal is to know when to stop, so resources and builders go to more important buildings. ■ Resource production buildings Farm / Lumber Mill / Wind Power Plant / Houses / Wanderer Camp: LV.20~24 is enough. Even top spenders rarely push farms past LV.24 — not worth heavy investment. Why: building output grows slowly, while your main resource income later comes from boxes, events and raiding. Pushing these buildings high costs a lot of builder time for a small share of production. ■ Support buildings Hospital / Villa / Library: LV.20~26. Hospital is personal; past LV.24, return on time and resources drops sharply. Players who fight often may push the Hospital a little higher to hold more wounded troops. Development-focused players can stop at the low end of the range. ■ Hero training buildings Refinery / Training Ground: moderate value. From HQ 30+, hero XP becomes extremely scarce. Because hero XP is scarce at high HQ, every source of XP has value. Still, do not let these buildings cut into the HQ chain queue. ■ Assembly Square Assembly Square: recommended LV.25 ■ How to use this list 1. Mark which buildings have reached the recommended level and stop upgrading them. 2. Only use a spare builder on buildings below the recommended level when the HQ chain is waiting (short on resources or all main builders busy). 3. After each major update, check whether any building gained new features.