Hi all, Hit a very random issue with Premiere Pro CC 2017 after several days of editing where, suddenly, Premiere was prompting that it had to "render required files" every single time on playback, regardless of how many times I pre-rendered the timeline. On top of that, playback and jogging was nonexistent and incredibly slow. The "required files" dialog is almost always something to do with Premiere needing to preview the AUDIO correctly, not the rendered video clips themselves. I recalled having a similar problem in the past, and sure enough, deleting all the muted audio on my many clips fixed the issue. Turns out one of the clips was a very sped up video for a timelapse - I remember that Premiere has big problems playing back super sped up audio, even if it's muted. If you're running in to this problem, be sure to DELETE all your audio and work out the kinks over which clip is causing the hangups. Hope this helps!
Thanks for taking the time to write that out, I'm sure it'll help somebody!