Comment by danpalmer

Our standard is that when a reviewer is no longer in flow, review should be the next thing they do. The SLO is 1 business day, which is supposed to be the maximum, and the guidance suggests it should be far lower than that. In reality, it varies wildly by team.

I find most of my PRs being reviewed by my team, on the same timezone, are reviewed within a few hours, but I suspect a big part of that is that most of my PRs are very small (they're actually CLs not PRs, and closer to a single commit in some ways, although hard to draw specific parallels to Git).

It depends on the language/ecosystem a bit, but normally I'd try to keep changes under 100 lines for an efficient PR process. Up to 500 lines is manageable but much slower. Over that is just impossible to do good review on.

Something that my previous company had a lot of success with was review by commit. Making sure that the series of commits in a PR "tells a story", with each one being simple and obvious, and then instructing reviewers to review commit by commit. It can speed things up and increase the quality of review substantially, but does require a bit more work from the author.