I’d assume that Bazel is smart enough to only recompile the pieces that actually changed in there, so the impact will vary depending on the actual updates we’re picking up.
As a workflow, when I use to develop in LLVM on a laptop, I would have a cron script that would run a git pull and build at 7am before I show up in the office so that when I arrive I have the most recent copy of the code with the build cache up-to-date