Code Review: How long is a peer code review?
The code review process has been researched and studied since 1976, and it has be established and re-established that the maximum product code inspection rate is 200 lines of code per hour.
“This is direct and conclusive evidence that reviews should be limited to around one hour, not to exceed two hours.”
– Jason Cohen
I’ve observed that the average developer creates around 100 lines of code per day in an agile environment. So I expect the average initial review in a peer review to last about 30 minutes. Now since there is usually a cycle of inspection, clarification, and rework, the end to end process of a peer review will vary based on the amount of back and forth clarification communication and the amount of rework that needs to be done. Teams should plan accordingly.