Two rules: (A) change gear per activity; (B) equip only for the moment you need it. Crowns map to action speed: Strength=construction, Intellect=research, Agile=crafting equipment, Martial=training troops, Medicine=healing/siege repair, Durable=building traps. Horns: War Horn=march size/capacity, Courage Horn=march speed, Justice Horn=march speed to monsters, Loyalty Horn=resources carried. Crystals: gather-speed crystals = Light/Wood/Thunder/Golden (typed per resource tile); resource-recovery = Earth/Water/Wind/Fire; production-speedup crystals are the exception you leave equipped. Combat gear (staff/grail/decoration) swaps per fight: hunt monsters with cavalry-type Thunder set; for PvP match your main unit (ranged = Wind). CRITICAL timing: a construction/research/etc. buff applies ONLY if equipped exactly when the action starts - equipping after start does nothing, and you may remove it immediately after starting. Gathering/carry buffs (crystals, Loyalty Horn) lock in only when troops ARRIVE at the resource tile, then can be removed. Save presets via the armor icon (upper-left of the equipment screen).
Original research source: Evony Guide Wiki
