I am reminded about an OU TV programme I saw many years ago when mathematicians word long hair, and paisley shirts with rounded collars.
The programme was essentially about Just in Time against the Cost of Holding. It was an excellent programme for I can remember it like yesterday.
They used a coal mine of the NCB as the illustration. They said how the mine usd some 10,000 nails per week, they costs little and they could be supplied on a weekly basis with an emergency buy if required. To hold 4 weeks or more supply would cost little but there was no advantage as the ordering scale and consumption were optimal.
The other item was a pit head winding wheel. The wheel cost £100k, it may not be needed for a year or 2 but if required would take 2-3 months for delivery. If there was a wheel in stock it would only take a week to fit. The cost in loss production would be about £5m. It was easy, in this illustration, to balance the cost of holding £6,000pa (assuming 6%) against the cost of not having it when needed.
Now in the Service there is a capital cost in holding but there is no cost attached to the waiting period - no cost in money terms unless we have to hire in paid help like with the Belfast's that we had to hire back from Heavylift in '82.
Did the bean counters miss the point?
Why order 2 washers? Order the whole box.