When I was back and doing 12wbt hard core I never really *got* rest days.
Well - sometimes I scheduled them in - but they were rest days in disguise. No gym smashing but maybe a 5-10 km walk instead. I couldn't get my head around actually just "resting"
I was sort of like the minions in this pic. I knew what I was doing when I was smashing it up. But rest - no clue. Rest days to me meant going completely off track and losing total sight of my goals. I think I was terrified to take them.
You know what though - it didn't work. I would be fine for weeks then burn out or lose focus - I just couldn't keep going at that pace.
This time - I am embracing the rest day. This thing is for life - and life is far too long to smash your body.
Still eat well. Still be mentally on track - but totally totally take a day off training.