tl;dr:“50 lines is a sweet spot across speed, review comments, revert rate, and total coding volume. If you’re willing to accept a range, I can recommend 25-100 lines per PR. According to the data, we see that time-to-review, time-to-merge, and review comments per line all get better the smaller you make your PRs. There is a limit though: under 25 lines, and you start suffering a higher revert rate, as well as a lower total code shipped.”