Build vs. buy gets framed as a features question, does the off-the-shelf product do what we need? The real question is maintenance: who keeps this running for the next five years, and what does that cost?
Buying shifts the burden to a vendor, good when the problem is generic and the vendor is stable. Building makes sense when the workflow is specific, the data must stay in-house, or the vendor's pricing scales against you.
The deciding factor is usually the workflow. If the system has to match how the office works, not how a product assumes it works, building wins. If the process is standard, buy and move on.
