How Specific Should a Learning Goal Be?

A goal needs enough shape to guide the next step—but not so much that a changed week makes it useless.

For example, “learn more about a subject” leaves the starting point unclear. But a rigid daily schedule may stop fitting as soon as your time or energy changes. Where do you draw the line between a goal that gives your learning direction and one that adds unnecessary pressure?

What helps you make a learning goal clear enough to begin, while leaving room to adjust the method?