On one page, a shopping list interrupts a sentence about memory.
This is part of the notebook's usefulness. It receives whatever arrives, without requiring each thought to explain its importance. A description of the morning can sit beside an address and a question that will remain unanswered for months.
The pages become interesting when I stop trying to make them presentable. Crossed-out words show where an idea changed direction. Repetition reveals what has been occupying me without my knowing it.
Occasionally I look back and find a line I could use. More often I find evidence of an ordinary day that would otherwise have disappeared.
That seems reason enough to keep a pen nearby.