John Scalzi, successful sci-fi writer, gives his perspective on how to think about writing and money. Strike “writing” and replace it with any other kind of independent work, such as speaking, consulting or development, and it is still excellent advice.
Come to think of it, most academics I know fall firmly in the “dont’ quit your day job” category – with the exception that most of them do the extra bit in order to afford being an academic…..
Oh well, perhaps it is time to write that book. On salaried time, mind you.