Forward pick and reserve serve different jobs
A pick face is designed for efficient order selection, while reserve storage holds replenishment inventory. Making every pick face very large may reduce replenishments but consume prime space; making them too small can create constant replenishment activity.
Use demand between replenishments
A practical starting point is the expected quantity required between planned replenishment opportunities, adjusted for variability and pack size. High-volume items may justify larger forward locations than slow movers.
Watch replenishment congestion
Frequent replenishment into active pick aisles can interfere with picking. Capacity decisions should therefore consider when and how replenishment occurs, not only how many units fit.
Re-slot as demand changes
Pick-face sizing should be revisited when velocity changes materially. A static assignment can waste space on declining SKUs while new fast movers overflow.
Practical questions
Should I use one utilization percentage for every warehouse?
No. Inventory profile, storage system, seasonality, staging demand, handling equipment and workflow can make the same percentage perform very differently in two facilities.
Can this guide be used to approve a rack or building change?
No. It is a planning resource. Structural, fire, building, accessibility and workplace-safety requirements must be established for the actual facility by the appropriate qualified parties and authorities.