I subscribe to one of those grocery delivery services that send you the ingredients for three beautiful meals that were planned by some reasonably interesting chef. They send you a little recipe book with beautiful full color photos of the quinoa fritters you are going to make this week.
Except I never make the fritters. In fact, most of the time, I don't even know what the meals are supposed to be. I just open everything up and then cook whatever I want with what's in the bag.
I also never read instructions for anything. I'm happy to install my own AC without looking through the pamphlet with the tiny print. It's not really that rebellious, but my family does joke that I don't like being told what to do. Which is accurate.
I was thinking about this today as I was making mint/mango/cucumber salad with lime (I seriously don't look at the recipes) because I had a person I train contact me and ask about rest days. They wanted to know how many days they should come to class and what day was the best to rest.
If you are a professional athlete, then there is likely a more precise answer to this question. But if you are just a person who moves, there really are no rules. Yes, you need to rest. But if your rest day might be the day you have to pick the kids up from softball or it might be the day your legs feel like they are going to fall off. Because we don't program how we move in life (one day you might help a friend move the next you might be stuck in front of the computer for 10 hours), the answer to your question depends on how you feel.
I know people feel safe with rules. People like to follow programs and recipes. But the problem with all these hard and fast lists is that they don't make room for life. Life doesn't have edges. You can be strict until the day you can't, and then what? But if you can be fluid with your training and adjust based on the moment, you leave room for creativity. You also become an active participant in your fitness--and the truth is, you are the only one who knows what you are feeling, which means that you are the primary expert in your body. Yes, having a plan is helpful, but planning also limits you. I notice frequently that when people miss a step in their very strict program, they are more likely to abandon ship. But that makes no sense. If you break one dish, you don't smash all the others.
One thing my clients often lament to me when their eating habits falter or they miss sessions is, "I was so good." As if now they are bad. You are the same. You are just doing something different at this moment. You are not following a certain rule.
Your month long detox or 6 week six pack program is finite. Hopefully, your health is not. So while it can be fun and important to be rigid, it's not sustainable. And the sooner you can learn to make your own rules based on your own experience, the sooner you can take ownership of your training. Rest when you need to, work when you can. Practice pullups and rollerblading, if that's what you want. Take a day off. Don't take a day off. Let it be your decision.