Buy SaaS when the problem is common, the vendor's objects match yours, and switching costs are low. Build when your handoffs, exceptions, and data ownership are the product. Integrate when accounting, payments, or CRM already work and the pain is the glue.
Most stuck teams try to buy their way out of a custom problem. The spreadsheet survives because it encodes reality the SaaS cannot express.
A simple decision test
If two competitors could use the same tool with no changes, buy. If your process is how you win clients or keep margin, own the software. If you only need a field sync, integrate. If you are unsure, map one workflow first (Workflow Leak Audit or SaaS Escape Audit) before committing to a platform.
Cost honesty
Custom builds have a clear range on our offer pages. SaaS has a lower sticker and a higher long-term tax when the team invents workarounds. Compare five-year cost of ownership, including people time, not just monthly seats.