Ok, we're about to get a bit philosophical with this one, but trust me when I say it's actually the most important one of all.
Embarking on a journey of productivity and self improvement is exactly that - a journey.
It's not like you do some reading, figure out the optimal habits to improve your productivity and self development, start doing them and repeat daily forever.
Just like improving yourself is a journey, improving how you improve yourself is also a journey.
Restated another way, your "system" (see last piece) should incorporate a regular review process where you step back, reflect on what's working, what's not towards your goals in life, and see if there is iteration and experimentation that should be made to it.
Let's make this a bit more concrete with a couple of examples.
First, let's say you need to get in shape. You've decided that in addition to eating healthier, for cardio you'll take up running every morning - great! However after a month of sticking to it, you're finding it lonely and uninspiring, and are struggling to get to it each day. Rather than abandoning the important goal of getting consistent cardio, you reflect and realize what you are missing as an extrovert is social interaction. So you adjust your plan to find a running group or buddy, which ends up working much better - running is now fun! And something you now enjoy doing rather than feeling is a chore.
Another example. Say you have an ambition by next year to start your own business, say a local marketing agency. To launch your own agency you'll need to have a network of potential clients, contractors, collaborators etc. So you set up a goal to reach out to someone new each day, with the aim to start building relationships in advance. All good! However you're finding it tricky to find folks on a consistent basis and schedule the calls. So after reflection, you decide to take another track and start writing useful content to share into local groups, and actively start helping folks out with marketing tips. In doing so, you're making those connections more naturally and also building up your reputation in advance of the launch.
Both of these cases are great examples of why it's important to have regular reflection and readjustment to your habits, routines, actions - to your system. Without it, you could have simply abandoned them and left with the wrong conclusions - "running is not for me"
But let's say in those two cases you didn't have that reflection and just eventually gave up in frustration. That wouldn't have taken you away from, not towards your goal.
The lesson here is that it's important to have a mechanism to continually try, learn and adjust. In some circles this is referred to as the "lean startup" approach, with the goal being to constantly iterate your product (in this case your productivity system) to get increasing success from your actions.
Personally I like to call it the "meta". In my case, every Sunday night I sit down and spend a few minutes on the meta - looking at my routines over the past week, seeing what's working, what's not and setting new changes for the new week with the goal to get to my goals faster. Sometimes there are a lot, sometimes there's only a minor tweak here or there.
But no matter what, the routine to assess my routines always stays in place.
No matter how you do it, I hope you also see the value in investing in your meta. It's arguably the most important thing you can do for lifelong self improvement.
Now live long and prosper!
ps - when you're doing your adjustments to the routines, don't only look to what's not working and needs to be changed. Take inspiration also from what is working and try doubling down on that approach. For example if you're finding it fun to "gamify" your workouts, can you do the same with your household chores? If you find that getting your meditation in the morning gives you more of a sense of calm that lasts through the day, would it be worth to try moving your journaling earlier as well?