The way you define yourself as a writer is that you write every time you have a free minute. If you didn't behave that way you would never do anything.
The writer who loses his self-doubt, who gives way as he grows old to a sudden euphoria, to prolixity, should stop writing immediately: the time has come for him to lay aside his pen.
The writer who possesses the creative gift owns something of which he is not always master- something that at time strangely wills and works for itself.