When should I IF? How long? When should I eat? How much? Is it okay to eat this before working out? Is it okay to eat that after working out? How should I exercise?
Schedules and regimens can help a person ease into a new lifestyle, but the sooner you learn to live without them, the better. In the paleolithic world, one of the very few set things would have been the rising and setting of the sun. Most everything else would have been unregulated, difficult to predict, foolish to rely on; in a word: organic. Yet that was, as we all know, the environment we thrived and were most healthy in.
15,000 years later and we've developed a relationship with the world that is more mechanical. Biological processes are understood in much the same way that mechanical ones are. While certainly not "wrong," such an understanding does colour one's attitude towards nature and one's own body in a way that tends to be rather cold, demanding and above all alienating.
We must always keep in mind that we are not machines and cannot expect ourselves to function in the same way all the time in any given circumstance. Nature (and I include ourselves as an inseparable part of nature) is too complex to be understood like a textbook, and when we insist on regulating most aspects of our lives, it leads to stress when things don't work out like we anticipated. The best tool we have for understanding what's going on is how we feel.
Don't feel hungry after a workout? Don't eat. Feel lightheaded and jittery halfway through every workout? Maybe try eating something beforehand. Feel perfectly fine without breakfast every day? No need to feel guilty and force something down in the morning. Feel sleepy around noon? Stretch out and have a short nap.
Then, just for fun, every now and then deliberately avoid catering to your body's non-pressing needs (pressing needs being things like elimination, drowning, gushing neck wounds, etc) to simulate difficult times out on the savannah.
It all sounds pretty obvious but it's so easy to forget.