I find that my memory has some strange associations. Case in point: while out for a jog recently, I saw a Trane van, and the first thing that came to mind was "retainage."
Trane Company. They make and service HVAC systems of various kinds. One of their business lines is large installation and maintenance projects, where high-capacity central HVAC systems are installed for big buildings: schools, office buildings, factories, etc. A good chunk of my time as a consultant involved learning how that project business worked in order to design integrations between various software packages.
The most complex integration that I worked on dealt with the project tracking system sending accounting information to Trane's corporate billing system. For reasons that I don't fully remember, it wasn't possible for either of those systems to make a lot of changes, so the integration software had to do a lot of calculation and data transformation. That meant that the designer - me - had to know exactly what the integration software was supposed to do with all these accounting transactions.
At that point in my consulting career, I had just about zero experience with accounting concepts. My specialty was the technical aspects of the integration system, not the business process analysis that led to integration design. So I was doing a whole lot of learning on the job while trying to understand how the projects system would send their accounting transactions, and what the billing system needed to receive. The most complicated part of the process was calculating retainage.
When you have a large project under a long-term contract, there's a natural tension between the client wanting the work done before they fork over payment, and the provider wanting to get paid on a more timely basis. The compromise that's been developed in the construction industry over many years has the client paying on a regular (usually monthly) basis, but a portion of the payment is held back (or "retained") until the project is complete. If the provider doesn't finish the project, they never get that retainage payment at the end.
So here I was, a complete neophyte in accounting concepts, trying to design an integration solution that would translate the project system's numbers into the accounting transactions that the billing system was expecting. Retainage was particularly difficult since the project system's numbers didn't have all the detail that was needed for the billing transactions, so the integration design had to fill in the gaps. I remember spending many hours in design sessions, doing my best to understand as various Trane employees explained the process - which seemed simple to them, as they'd been doing it for years. I was fortunate that those folks were patient and willing to help me get up to speed on a completely foreign subject. I particularly remember a guy named Dave spending hours in meetings and conference calls explaining all the complexities of retainage while I tried to capture it all for inclusion in the integration design.
I spent a lot of time working at Trane, well beyond just this one project. But the whole experience of figuring out this design left quite an impression. Enough that seeing a Trane logo in passing on a van, even all these years later, brings it all to mind.