Arbitrary demarcations can still be valuable! Just because something is arbitrary doesn't mean that it's not helpful. Working in chunks will let you take more time to review each callsite individually, and increase your confidence in the changes

In the future, I would definitely encourage you to explore a more iterative solution—fix the first 50 occurrences first, or maybe all the occurrences of a handful of functions. For example, if you have utility functions A, B, C and D, maybe fix functions A and B first, and then C and D second.

Ultimately, at the end of the day it's going to depend on how much code you're touching. If you're only touching 100 library calls, then it's probably easy to do them in one PR. But if you're updating 1000 library calls, you'll need to take a more iterative approach. Building those skills now will serve you well in the future when working on bigger codebases and harder refactors.

Well another problem is that there was a developer also working on those functions at the same time. So just like the recent post on a 25 million LoC reformat done in a weekend, it seemed better to do it in one fell swoop. If it's good enough at 25 million, I'm sure it's good enough at a few thousand