It does not seem that long ago, although it certainly was, that the world marveled at the Japanese system known as just-in-time manufacturing.
The system, developed by the great Toyota production boss Taiichi Ohno, revolutionized the manufacturing process. It received international acclaim and was adopted by just about everyone around the world. It was efficient, effective and certainly economical.
The process is simple. As a supplier, all you need to do is make sure that your parts show up at the assembly line at precisely the right moment for installation on whatever is being made. You don't have weeks of inventory sitting in a corner of the plant.
The method has been used for decades without many hiccups, although lately some monkey wrenches have come flying into the process that have created challenges in the auto industry. If you rely on a single-source supplier and something goes wrong, watch out: There is trouble in River City. The assembly line is going to run out of parts, not overnight but right now, and the plant goes down.
If the vehicle you are producing has enough volume, then you might have a couple of sources for parts.
The second supplier can swing into action, and you can possibly get by until the original source becomes available again.
As more troubles have occurred in supplier plants, it has become obvious that you need a backup when you have a vehicle line running at just about full speed all the time.
By the way, the idea applies to people as well. Unless you get to a certain size, you can't always afford a backup for your key personnel.
If the key executive gets hit by a bus, there is no one around to fill the person's shoes immediately.
Every system, whether it's manufacturing or personnel, needs a fail-safe. It needs to match just in time with just in case.
Just in time has been good for the industry, but as the famous manufacturing engineer W. Edwards Deming would have said, you have to keep improving the system.