I recently wrote a post on how there is no "there" to get to and it is vital for your own happiness and wellbeing to learn to enjoy the path and not obsess about the destination. In that same vein, I've also come to realize that there is no "lifestyle" or "routine" to get to either.
What I mean by this is no that you can't develop healthy habits or a good routine. Those things are in fact, vital to develop. What I mean is that you will never get to a point where you will always do those things. You will always be interrupted by travel, emergencies or just falling back on old, bad habits.
In the same way that life will come with good times and bad times, your habits will ebb and flow. Your lifestyle will ebb and flow. You'll get to a place where you feel like you're doing everything right and then it will break down and you'll have to build it up again.
You'll hear a lot about this or that habit that billionaires or super successful people have, but I can guarantee you they don't always have those habits. Sometimes, they'll fall out of them and have to get themselves back into them. It will ebb and it will flow as it will with even the most disciplined and successful people.
One time after a football game in high school, one of our coaches chastised us by saying "you guys get too high when good things happen and too low when bad things happen." This is why this concept is important. You should expect to fall out of good habits. No you shouldn't try to fall out of them, but it will happen nonetheless.
You should, instead, try to develop the best habits you can, knowing that they will break and you will have to fix them. This self-knowledge will allow you to cope more effectively for when things do fall apart. The worst thing you can do is mope and become depressed about it. If you know it will happen, then you know it was just an inevitable stumbling block you will now have to overcome. Predicting problems in advance (including perpetual problems, such as this) makes those problems easier to deal with.
Hopefully, as you continue to work on self-improvement, each plateau will be at a "higher" place where you are acting even more effectively. The highs will get higher and the lows will be less low. But this isn't necessarily going to be the case. And knowing that life isn't a linear progression is one of the best ways possible to "give yourself a break" and learn to enjoy the path rather than obsess over the destination.
"Every day is a new life to the wise man."
The Righteous Mind
Star Slate Codex
Consulting by RPM