Dragging Marley's chains

I noticed that today is the anniversary of Charles Dickens' publishing of A Christmas Carol so it seems like a good time for this post:

I have worked at my present job since 1988. Our company designs, manufactures and sells electronic equipment and there have been a number of different versions and variations of these units over the years. Since I've worked here so long, I am often the person the newer employees go to when they want to know about the older models we made years ago. I describe it as "dragging Marley's chains" when I need to take time from my current project to explain something about an old project. My description comes from the scene in A Christmas Carol where Ebeneezer Scrooge's long dead partner, Jacob Marley, appears to Scrooge on Christmas Eve to warn Scrooge that he is headed to the same fate as Marley - that is Scrooge will be dragging his own, longer chain around with him in the afterlife. Marley describes it as,

"I wear the chain I forged in life," replied the Ghost.
"I made it link by link, and yard by yard; I girded
it on of my own free will, and of my own free will I
wore it. Is its pattern strange to you?"

Scrooge trembled more and more.

"Or would you know," pursued the Ghost, "the
weight and length of the strong coil you bear yourself?
It was full as heavy and as long as this, seven
Christmas Eves ago. You have laboured on it, since.
It is a ponderous chain!

from the Project Gutenberg entry for A Christmas Carol

It's a puzzlement. While it's a good thing to take an interest in all of your company's products, it can also be a burden.While working for a company for a long time (in my case, 22 years next month) can be a good thing, it can also mean that you're dragging along the knowledge you've gained in those years. While having a broad-based knowledge can be good, you limit the amount of time you have for learning more about a specific supject.

I know a lot of people that always plan on working for a company for only three to five years so they can leave all the old stuff behind. They want to move on to the next new thing. I, on the other hand, like to refine and improve the things I work on. My favorite product was a programmable controller that had no hardware changes for over ten years but was continually improved by rewriting its firmware (that's a program that is burned into the memory of the board). We never had to change the way the board was manufactured. We improved it by modifying what was loaded into its memory.

So, here I sit, forging more links into my chain. A chain of knowledge and memory.