The useful idea
Automate when the full workflow becomes more useful or economical, including the work needed to keep it reliable.
Count the real work
Consider how often the task happens, how long it takes and what errors cost. A job done twice a year may not justify a custom tool.
Look at the exceptions
Stable inputs and clear decisions make a better starting point. If every case is unusual, automation may simply move the work into checking and correction.
Try a representative batch
Compare the current approach with a small pilot. Include the time spent reviewing output, fixing mistakes and maintaining the workflow.