The above statements are things I have experienced. For instance, the second sentence states "output doesn't equal input." That means recovery, after one has expended energy, takes longer than someone that does not have CFS. I have to consider the effect of work on my hip joint too. If I overdo, I pay in pain. So I rest often, and I consider this a normal part of my day. I may not get all the things done on my To Do List, but I can go back to it: knowing this keeps me from worrying that I will never get done.
Working in 7, 10, or 15 minute blocks of time can also be helpful. If I am dealing with a more fatigue, I work in 7 minute increments. That may not sound like much, but it's surprising how much can be accomplished when one works and rests in blocks of time. Adjust the blocks according to your own needs. You will see progress over time. Just try not to add to what you have started to clean: that means pick up after yourself. An example would be hanging a clothes item up, or putting it in the dirty clothes, rather than throwing it on the floor.