Me: OK, I have to get systematic about testing out this change I made, let's figure out what all has been affected by this rewrite.

Code: Yeah so turns out like 15 of the 70 APIs you modified aren't actually called by anything anywhere at any time and should have been deleted, I dunno, four years ago?

17 have proved to be unused by anything.

There's also two more used only once by something everyone agrees we don't need anymore, but _for the moment_ they're _technically_ needed.

Another one used by that thing everyone agrees we don't need anymore.

I've got through 55 of the 70, by the way, in case you want to project how many useless APIs I dig up.

18 unused APIs, plus three that are used by something we're going to be dumping.
And that's the final count: 18 of these 70 touched APIs aren't used, and three more are going to be unused soon.
Also four more where I have notes like 'this use is way too spaghettified' or 'fix this name' or in one case, 'What'.