There is no "system" for personal productivity, and anyone who attempts to sell you on one is trying to get you to buy in to the “self-help snake-oil.” There are tools, techniques, skills, tips, and possibilities, but any one all-encompassing, fixed and unbending system is doomed to eventual failure. No system exists that can handle all aspects of the complexity of life.
Not my life, not your life, not anybody’s life.
Claiming that you have a "personal productivity system" is like claiming you have "a car." Call it a two-door hatchback Honda Civic.
Today you need to pick up your best friend and his future wife to be and take them to the church for their wedding. Tomorrow you are going to Home Depot to haul 1,200lbs of lumber back to your home for a construction project.
The day after you will take a romantic drive down the coast with your girlfriend, with the top down, only your Honda Civic doesn’t have a soft-top. And the day after that you are going to enter, and try and win, the Indy 500. And the day after that you are going to drive the Dakar Rally. And the day after that you can haul the 35 feet, fifth wheel toy trailer with your quad bikes in tow out to the dessert for a little bit of much needed R&R.
See how this “reference” to “a car” is a Goddamn joke just like any reference to "a system" is a really bad joke.
Anybody who realises that you cannot do all those activities with a single, "multi-purpose" vehicle, no matter how versatile it might be, must also realise that you cannot even attempt to tackle all of life’s complexities with a single "multi-purpose" system for personal productivity.
To boil it down to something almost anyone can understand, "The right tool, for the right job."
If you are clinging desperately to a single system to organise and drive your life, you are doing yourself a major disservice.
Stop it, right now, right here, today. Resolve to say to yourself, "I don’t believe in any one system, every tool has its purpose, and every solution has a tool for it, but no one tool exists that can fix my entire life." Your goal for personal development and self-improvement, from this point forward, can only be to research and adopt as many different tools and techniques that have been proven to work, and regularly practice how to apply them to the problems they are good at fixing.
Or you can keep believing in one system to fix your life until the next great and perfect system comes along that will fix your life for you (again).
It’s up to you.