This sexy diagram shows clearly where time should be spent

Ten hours is ten hours, and they are the SAME whether you spend them watching TV news ($0 value) or surfing the Net to acquire valuable technical papers ($5 value) or attending a course/workshop to increase your professional knowledge ($30 value) or increasing/refining your instructional material for teaching purposes ($100 value).

The above diagram simply shows the different "returns on investment," depending on where you choose to spend your time.

Of course, this is a free country, so you can choose WHERE to spend your time, but you CANNOT choose the professional/career/financial consequences of where you spend your time.