Identify a persistent constraint
Custom software is worth considering when an important workflow is consistently constrained by tools designed for a different process. Look for repeated data entry, unreliable handoffs, inadequate permissions or integrations that have become business-critical.
Confirm that the problem will persist. A short-lived campaign or a process still changing every week may not justify creating a long-lived application. Improving the process can sometimes remove the need for new software.
Compare realistic alternatives
Evaluate configuration of an existing product, an integration between current tools and a focused custom component. Include the effort of adapting your process to each option. A product with more features is not necessarily a better fit.
Consider data access, vendor exit options, licensing growth and operational support. Custom development offers control but creates responsibility for maintenance, security, documentation and future changes.
Commit to an owner and a first release
A custom system needs a business owner who can prioritize tradeoffs and an operating team who can support it. Without those roles, even sound engineering can produce a product that nobody is ready to maintain.
Define the smallest complete workflow that would improve the situation and how the improvement will be measured. Use that first release to learn before expanding. The correct discovery outcome may still be to buy a product or simplify the process.