Most of us do not need another productivity system. We need a habit small enough to survive the commute, the school run, and a wet Tuesday in October.
Twenty minutes is enough to finish a chapter of a paperback, or two if the type is generous. It is also short enough that you can protect it: on the train, after the kettle boils, or before the news goes on.
At MRB Sell we keep hearing the same thing from customers who actually finish books. They stopped waiting for a free evening. They picked one chair, one title, and a timer. The books that work best for this are not always the thickest. A well-paced novel, a calm self-help guide, or a short history you can enter in pieces will beat a stack of intention every time.
If you are starting from zero, choose something you already want to talk about. Leave it where you make tea. Read until the chapter break, not until you feel virtuous. That is how twenty minutes becomes a shelf.