Cal Newport writes:

The Law of Action Planning: No rigid rules or systems for figuring out “what to do when” can work effectively for more than a few weeks before becoming obsolete.

I’ve found that this applies when I’m using my own productivity system. I’ve invested serious thought into my own system—effort that pays large dividends. At the same time, my system is constantly changing over time. I might fiddle with one knob every week or so as I notice that features of my system become less relevant or if I think of ways to improve the system.

So my productivity system is less like an architecturally planned building, with all features and their interactions planned in advance. It’s more like the mythological Ship of Theseus, which is replaced plank by plank until we can ask whether the ship is even the same ship anymore. But that’s beside the point—the important thing is that the ship gets us where we need to go!