Buying cages is not done once they are set on the floor; they must fit overall warehouse management. Plan on three fronts. First, by plant structure. Clear height under beams sets how high racks and stacks go; column and beam positions affect layout; floor load and flatness decide heavy-rack feasibility; fire and lighting positions must be avoided upfront. 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, not today's volume. Third, balance accessibility against density. High density costs easy access; easy access costs density. FIFO and slot numbering are settled at the planning stage. Settle these three and cages will actually turn in your warehouse.