Cages are a major logistics container in storage and transport: fixed capacity, neat piles, visible contents, fast stocktaking, and better space use. They fold freely, storing flat when idle to save warehouse space. How do we design for practicality? Nanjing Tongnuo Storage Equipment Manufacturing Co., Ltd. works on three fronts after years in the trade. First, by plant structure. Clear height under beams sets rack and stack height; column and beam positions affect layout; floor load and flatness decide heavy-rack feasibility; fire and lighting positions are avoided. Second, by cargo traits. Outer dimensions set cage specs, cargo weight sets strength rating, and whether the unit is a pallet, cage, or single item sets the container. Estimate slots with two years' growth in mind. Third, balance accessibility against density. High density costs easy access; easy access costs density. FIFO and slot numbering are set at the design stage.