I built too many grain and lumber farms, how can I make room for training tents?

What you can do is demolish the ones with lower levels. Be mindful though that this game does not offer the option to keep them with the level of upgrade that they have. In any case, you'll probably better off using your troops to gather resources outside the kingdom instead of relying heavily on resource-producing facilities in your capital. It is more important to prioritize hospitals first, followed by training facilities, and lastly the resource-producing facilities for quarts and iron.

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