I usually go to the gym M-F without a break day. I think I vary my workouts enough so the wear and tear is not bad and nighttime recovery is possible.
If you follow a training plan for a race, there are rest days built in. Cool running has several training plans for several different race lengths. I tried to skip rest days, but my body ached. I ended up doing 6 rest days mixed in the last 2 weeks because of a mild injury.
Upping mileage is supposed to be 10% per week. We started training 4.5 weeks before the race and not the 8-12 recommended. The other thing is 75% of your running should be done at an easy pace, meaning you can still talk while running. Next time I will follow the plan more closely. Some days I just wanted to get the miles in and ran faster than was specified.
It has taken 2 weeks post-race for my body to recover. I have been using the elliptical and lifting, not running much. Hopefully, this week I can kick it in gear. I will listen to my body and take rest days as is needed. Not enough sleep, sick kids, sore feet, take a rest day. You can make it up your next run.