Sunday, April 7, 2024

April 2024: The Lifespan of a Part Number: "Back Then & Today"

Over the past 40 years or so, the number of part numbers in some automobile manufacturers' parts catalogues has grown as much as 25 times the number of part "numbers" today versus back then. This is simply evident by the increased number of manufacturers and increased number of vehicle models.

That being said, the "Lifespan of a Part Number" has drastically changed over this span of 40 years and beyond. But when we talk about the lifespan of a part number, there are actually two different meanings, or definitions of this lifespan.

When we talk about the "lifespan" of a part number from the manufacturer's standpoint, we are referring to "how long" the manufacturer will carry this part in their Master File before it becomes discontinued and it's "shelf life" has expired.

When we talk about the "lifespan" of an automotive part from a consumer standpoint, the "lifespan" of an automotive part means "life expectancy". How long will the part last before it breaks or wears out.

Back in the day, the "lifespan" of an automotive part from the manufacturer's standpoint was actually much longer than it is today. Years ago, many part numbers fit several vehicle applications for several years and often times we could memorize part numbers because of the frequency of use in multiple applications.

For example, one set of brake pads could fit seven different applications for several years where as today, this is quite the opposite. We could have seven different brake pad numbers for just one model vehicle application over a much shorter time.

The result of this swing increases the number of total part numbers that a particular manufacturer carries in the breadth of their inventory. More increases are even realized by the increased number of vehicle models with the addition of hybrid and electric vehicles.

With this increased number of part numbers also comes the "decrease" in the lifespan of the "individual" part number. The result of increased inventory breadth and fewer individual part demands as opposed to multiple model and year utilization as mentioned above 40 years ago results to the "shrinking" of the lifespan of the "individual" part number.

"So, Just How Does One Definition, or Meaning of the Lifespan of a Part Number Affect the Other Definition or Meaning?"

The answer to that question is that the "Lifespan of a Part Number" is highly impacted by both definitions, or meanings. One affects the other in the opposite direction as one increases, the other decreases.

This may sound confusing, but after we break this down, we will see that it all makes sense, especially from a mathematical standpoint. As mentioned, the "Lifespan of a Part Number" can also be referred to as the "Life Expectancy" from either side, meaning how long will a part last on the vehicle, or on the shelf.

So, we actually have two scenarios involving this term of "The Lifespan of a Part Number". One being how long will that part last on the vehicle before wear and tear takes its toll. The second being how long will the part number last on the shelf before becoming obsolete and/or discontinued due to lack of demand.

Now, let's get into it and find out how each meaning affects the other in a huge way. We will see when one definition goes on the upswing, the other one tumbles.

Let's start with the "Lifespan of a Part Number" from a "life expectancy" standpoint, meaning how long a part will or would last after it is installed in a vehicle today versus 40 years or so ago. 

The technology in automotive manufacturing has certainly risen drastically over the past 40 years which is one main reason why the "life expectancy" of an automotive part, or automotive parts has increased. 

Many automotive parts have also been replaced with components versus "moving parts" that are more efficient and dependable. Some parts today actually have a "life expectancy" of the actual life of the vehicle with no expected replacement interval.

For example, 40 years ago, parts such as fan belts, radiator hoses, steel exhaust systems, biased tires, non-platinum spark plugs, and wheel bearings had shorter "lifespans". They either wore out or had to be replaced on a mileage or time interval basis.

Even vehicle fluids last longer today as opposed to years ago with longer life engine coolant, transmission fluid and synthetic engine oil. All going way beyond the old "life expectancy" of years ago.

Other parts that now have extended lifespan are belts and hoses as years ago, there were as many as 4 drive belts per vehicle. Fan Belts, A/C Belts, Power Steering Belts and some vehicles with Air Pump Belts have been replaced with just one Multi-Ribbed Serpentine Belt with a much longer life.

Radiator Hose replacement has almost become a thing of the past as these hoses, as in the previous mentioned "V-Belts" of the past would only last approximately two years or 30,000 miles much like steel exhaust systems, versus "stainless steel" exhaust systems today.

On the other hand, the "shelf life" of many parts years ago would have a much longer "shelf life" than parts today. This may sound weird, but it is true from a standpoint that many parts years ago fit for many years and fit multiple vehicle models and applications. The end result is the "need" for these parts lasted for a longer period of time.

As mentioned earlier, and for example, a set of brake pads for one manufacturer fit many models and for many years as opposed to today when we could have several different sets of brake pads that would fit just one year vehicle model due to various vehicle options and requirements.  

With more vehicle manufacturers, more vehicle models and more technology, the end result is that we have many more part numbers and a wider "breadth" of parts inventory within each manufacturer than we had several years ago.

That being said, more applications mean less overall "individual" part number usage even though the "overall" part usage may be the same. In other words, we could sell 10 sets of 10 different brake pad part numbers versus 10 of one part number, both equaling 10 total sets of brake pads.

In a similar comparison, in the airline industry, Southwest flies Boeing 737's exclusively. There for, the chance of having the right part for repairs and maintenance is more likely to be available than Delta who flies Boeing 717's, 737's, 747's, 767's and 777's for a longer period of time. Not only that, Delta also flies jets manufactured by Air Bus, McDonald Douglas, (bought out by Boeing) and Canada Regional just to name a few.

This means the likelihood of Delta not having the right part for repairs or maintenance is more likely to occur than with Southwest. It is also more likely that Delta has to have more "breadth" of parts inventory to maintain its fleet of various jets.

Back in our industry and way back in the beginning of the automobile assembly line, Henry Ford kept it very simple. One part fit all, and the Model T was only available in one color which was black. Mass producing of original equipment and replacement parts was definitely not an issue, especially in later years in the automotive parts aftermarket.

The number of vehicle applications that required the same part number years ago was much higher than it is today, even though there are far many more vehicles on the road today versus "back in the day".

When you have as many part numbers as we have today, it's really no wonder why there are more back ordered parts and supply chain issues. Even though some manufacturers do it better than others, it's quite clear that the manufacturers with more total models have more shortages and less parts availability than manufacturers with less models.

The "Lifespan of a Part Number" is affected by both definitions, and they actually play off one another. When one lifespan definition is extended, the other lifespan definition is diminished. The difference between the two again is how long will the part last on the vehicle versus how long the part will last on the shelf from an availability standpoint.

A part can be discontinued or go obsolete no matter what the part fits no matter what the year, make or model. I personally know of parts that are still available from a manufacturer that fit vehicles back in the 70's. On the other hand, I know of parts that have gone obsolete, with the part being discontinued, and the vehicle is less than 10 years old.

It all comes down to part demand and longevity from either one of our definitions of the "Lifespan of a Part Number". The definition of each terminology simply indicates demand is going to determine the fate of a part number or dictate the overall outcome of the individual part number.

One thing for sure is if we were to compare the "Lifespan of a Part Number" to our own lifespan, there are definite similarities. Each part number is really just a name, just like any one of us. A part is born, a part grows in demand, just like we do over a course of time, goes to work for a while, then demand slows down until we eventually retire.

In the end, just like us, parts are discontinued, and we move on past this life. And much like our own lives, some live longer than others as the part numbers do depending on the overall part demand.

So, next time you walk down that aisle and pass by some of these part numbers that you know and may we have in your parts inventory, just may be the last time you see each other, only just to remember that part number down the road when it becomes your time to look "back in the day"!

If you want to learn more about ACG Smart Parts "Eight Habits of Highly Successful Parts Managers", visit our website @, or...just pick up the phone and call me at :

(786) 521 - 1720...After all, not knowing is not worth not "fixing" it...