Custom AI Applications
Custom AI Applications vs. Off-the-Shelf: A Decision Guide
When the generic product gets you 80% and the custom build gets you the 20% that matters.
Off-the-shelf AI products have improved enormously, and the default decision has shifted toward buying. But a class of problems still rewards a custom build — and knowing which class you are in saves you from either overpaying for a generic tool or underinvesting in a core capability.
Buy when the workflow is standard
Support deflection, meeting notes, sales-call summaries, document Q&A — these are now table-stakes features in mature products. A custom build will cost more, ship later, and lag the vendor’s model upgrades. Buy them and move on.
Build when the data or workflow is proprietary
When the application must reason over your proprietary data, follow your specific workflow, and fit your access model, a generic product will fight you at every step. Custom builds win where the differentiation is in the data and the process, not the model.
The 80/20 test
A useful heuristic: if an off-the-shelf product covers 80% of your needs and the remaining 20% is convenience, buy. If the remaining 20% is the core value — the underwriting decision, the quoting logic, the compliance check — build. Convenience gaps are tolerable; value gaps are fatal.
The decision is not permanent. Start with the product, learn the gaps, and build only the part that turns out to be the differentiator. That sequence minimises risk and maximises the return on engineering spend.
