Holding stock in returnable boxes rather than decanting into fixed racking is efficient: fewer handling steps, no double counting, and the container travels with the stock. It creates one problem, which is rotation. In fixed locations, rotation is a property of the location. In boxes, it has to be a property of the box, and that needs a rule.
The box needs a date on it
Every box holding stock carries a date, written on a wipe-clean panel or on a card in a document pocket. Without a visible date there is no rotation, there is only whichever box is nearest. The date should be the date the stock went into the box and it should be readable from the aisle, because a date that requires handling the box to read is a date that will not be checked.
Position is the cheapest rotation system
Two-deep shelving with rear replenishment gives rotation for free: new stock goes in the back, old stock gets picked from the front. Where two-deep is not available, use position on a single shelf – new stock always goes at the right-hand end, picking always starts at the left. One rule, written on the upright, and the system runs without anyone making a decision.
Colour for the exception, not the rule
Colour coding by age band works where the age bands are few: current stock one colour, stock entering its last week another, and quarantine a third. It fails as soon as the bands multiply. Keep it to three and pair it with a date, because colour tells you to look and the date tells you what you are looking at.
What happens at the count
Stock counting in boxes is easier than in fixed locations if the box quantity is standard: count boxes, multiply. It is harder if boxes are part-filled, so set a rule that a box is either full or not in stock, with partials kept in a single marked location rather than distributed. A partial box on every shelf is what turns a ten-minute stock count into an afternoon. The counting discipline is the same one described in counting a box fleet monthly.
What happens when the rule breaks
Every rotation rule breaks eventually – a rush job pulls from the wrong end, a new starter does not know the convention, a delivery arrives and gets put wherever there was room. What matters is whether the break is visible. A date on the box makes it visible: a box at the front with a later date than one behind it is obviously wrong, and it can be corrected in seconds.
That is the argument for dating every box rather than relying on position alone. Position rules are efficient and fragile; dates are slower and self-correcting. Use both, and check the dates at the same monthly count that covers the fleet. Where a date is found out of sequence, swap the boxes rather than rewriting the date – rewriting destroys the information that made the problem visible in the first place, which is how a rotation system quietly becomes decorative.
What to do about partial boxes
Partial boxes break every rotation and counting system, and a plant that allows them everywhere will spend its life reconciling. The workable rule is one designated partial location per zone: every partial box goes there, nothing else lives there, and it is worked from first. One location is checkable in a glance; partials distributed across thirty shelves are not.
The partial location should be at the front of the zone, at eye height, and marked, because a partial box that is hard to reach becomes a permanent resident. Where the same part is picked repeatedly during a day, the partial location doubles as the pick face for that part, which removes the handling step of consolidating. Where partials accumulate and are not consumed within a day or two, the underlying problem is a pick quantity that does not match the pack quantity, and that is a purchasing question rather than a storage one.
What we can do
We build PP corrugated boxes with wipe-clean date panels and card pockets, and we will put the panel where it is readable rather than where it is convenient to make. Tell us how rotation is meant to work and we will place the label for it.