Intent of Just in Time

Underlying Reasons for JIT
Addae Michael
In my candid opinion JIT saves unnecessary cost incurred on stocking manufacturing materials in warehouses which include labor cost, cost on wear and tear and so forth. JIT therefore ensures prompt response to inventory requirements at less cost, In much the same way, finished products must be evacuated and distributed immediately to avoid holding cost. In principle I think JIT theory entails an in depth value chain analysis.

JIT implementation
Jose
Correct, but nothing is perfect, not JIT.
If manufacturer uses JIT to avoid stockage, who will keep the inventories: of course, the supplier!
If we, as manufacturers, want quick reaction to changes in demand, somebody must have our prime matters stocked ready to be delivered when required: our supplier!
Be careful, we can lose suppliers if we don't take care of them. Supplier-Manufacturer is a chain that must be solid and both must act as a TEAM.

JIT
William P. Gibbs
I agree, JIT is most effective when applied to the entire supply chain. If upstream suppliers are not producing to a clear "pull" signal then they quickly become repositories of muda.

Challenges Rather Than Disadvantages
Dela Agbo
If one sees JIT as a system of 'zero inventory' then one can have series of disadvantages in operating such a system. In fact such as system can best be described as ‘recipe for disaster’ However, if one sees JIT as a philosophy that is built on 'pull system' or on waste elimination or as a philosophy where other concepts like Kaizen, zero-defect, teamwork, quality circles and even TQM feed into, then one should be talking about ‘challenges’ and not ‘disadvantages.
Even the challenges ultimately become incentive for alertness, continual improvement and excellence. A ‘pull’ system implies striving for information excellence and so ‘no surprises.
Built in the JIT philosophy is the ff: Resilience, agility and ‘leagility’ [combining lean and agile]. The JIT philosophy therefore requires discipline; a call to duty for excellence. I see JIT as a means to an end of zero inventory; RATHER THAN an end of zero inventory in itself.