Rest Days for PE?

Hi all, I’ve been reading about the Newbie Routine and how it advocates for taking days off (e.g., 2 days on, 1 day off, etc.). I’ve also read about using extenders and how it advocates longer use — every day, multiple hours per day — since time under tension is key. The two seem contradictory to me and I’m wondering if the experts on this forum can opine on why there’s a difference between taking rest days for someone using the Newbie Routine and not taking rest days for someone who’s PE routine is more focused around just using an extender.

I never used extender, but suppose that is because two different approaches. Aim of extender is to do very low intensity stretch for 2-8 hours. You shouldn’t get any injury with that at all. On the other hard, manual exercises are about 10-30 minutes stretch with mid-high intensity and we probably get small injuries what needs time to heal.

But that question is interesting and important. It might explain few reasons why and how we can get gains.