Keep the spreadsheet when
The work is temporary or exploratory, one accountable person owns it, the data is low-risk, the logic is understandable, and errors are easy to detect and reverse.
Warning signs that it has become a system
- Several people edit copies or wait for one person to unlock the process.
- Formulas, macros, or hidden tabs encode essential business rules.
- Staff repeatedly import, export, re-enter, or reconcile the same information.
- Customers or managers depend on answers that the file cannot provide reliably.
- Permissions, approvals, audit history, validation, or recovery matter.
- One broken reference or accidental overwrite can interrupt operations.
The replacement may not be a custom application
A controlled shared list, database-backed form, workflow tool, configured business platform, or integration may solve the problem. Custom software is appropriate when the workflow and controls are specific enough that generic tools recreate the same workarounds.
Start with one complete outcome
Define the users, inputs, decisions, exceptions, outputs, existing systems, source of truth, security needs, and acceptable manual steps. Replace a bounded operational path before attempting to reproduce every historical tab.