Yes, your daily list of your Most-Important Tasks is like a magic ring that will enslave all other productivity systems and bend them to your will. It won’t make you invisible, though.
There is no such thing as a comprehensive productivity system. Even if you practice your productivity system of choice perfectly, it will never encompass all the things you have to do and distill them into a manageable, actionable list every day.
I generally follow Getting Things Done, but I have too many collection points (two email inboxes, two physical inboxes, Slack, Teamwork, Evernote, Remember the Milk, several calendars, and probably some other things I have not thought about) and two sets of lists (Remember the Milk for my stuff and Teamwork for work stuff), and I cannot do much about that. Oh, I could prune my app selection a bit, but there is only so much I can do, and it wouldn’t really help. I will always be split between work and home, and I will always use a variety of tools to communicate and write things down. Many people have their stuff even more spread out than I do.
Bringing it all together is a challenge that no productivity system adequately addresses. That’s why making Most-Important Tasks a daily practice is so important.
In any productivity system, figuring out what to do now is a challenge. It is more difficult than just responding to your most-recent email or looking at cat videos. That’s why we so often end up wasting time — or at least not doing the things we really ought to be doing now.
Figuring out your Most-Important Tasks is easier if you do it before you need to start doing things. That way, when you are deciding what to do next, you have a helpful, bite-size reminder of the three (or two or four) things you really need to get done.
Most-Important Tasks does not take the place of another productivity system if you are already using one. And you definitely don’t have to be using a productivity system already to get the benefit of writing down your most important tasks every day. MITs complement any productivity system — or none at all.
Daily MITs are really just a simple form of work planning — looking at all your lists and inboxes and calendars and figuring out what you actually have to work on, and when. Since we all collect our tasks in multiple collection points and wind up with to-dos spread out across multiple lists, we need to sit down periodically and distill them into a daily must-do list. Instead of doing this every time you switch tasks, MITs makes it a daily practice so you can spend your day actually doing things instead of figuring out what to do.
Because of this, MITs play nicely with any productivity system because they do not have to be a part of any system. Sit down with your system once a day and distill all your lists into just three tasks that you must get done today, and work from that list. If you do, you will be more productive every day.