> consume a significant amount of your dev efforts
If managing revenue is a core component of your business, as it is for most non-startup companies, in-housing a handful of API calls then transforming storing and visualizing the data is a worthy investment.
As the OP indicated they've barely had to touch it for 4 years. A couple weeks of effort and a few hours of maintenance here or there can be superior to another ephemeral third party vendor that can grind your core business to a halt with an outage, acquisition, pricing change, etc.
As you accrue more experience in the software industry, whether as an engineer or a technical founder, it's not as though you become capable of writing code ten times faster. What truly increases isn't your typing speed, but rather the leverage you gain from developing an intuition for discerning what to build versus what not to build, as well as what to purchase versus what to create from the ground up.
Furthermore, the situation isn't always black and white. There's a middle ground. Initially, you might lean on third-party solutions, gradually replacing them with in-house solutions bit by bit. You may even find yourself with a mix of in-house and third-party solutions. There's no need for it to be an absolute 100% in-house or 100% third-party solution. You could have a 49% in-house and 51% third-party mix, or perhaps an 80% in-house and 20% third-party split.
There are no standard templates to follow. It's all on a case-by-case basis. However, a general principle I found useful is that the more closely a decision ties to revenue generation, the more control you should ideally exert over it.
If managing revenue is a core component of your business, as it is for most non-startup companies, in-housing a handful of API calls then transforming storing and visualizing the data is a worthy investment.
As the OP indicated they've barely had to touch it for 4 years. A couple weeks of effort and a few hours of maintenance here or there can be superior to another ephemeral third party vendor that can grind your core business to a halt with an outage, acquisition, pricing change, etc.