If, on the one hand, it is very useful for an artist not to get carried away and to save some of his inspirations so that he can work on them better, on the other hand, he has to develop a very keen sense for recognizing his exceptional moods and ideas, in short, he has to know when it is essential to seize the moment. There are ideas that unfortunately pass, and states of mind that can only be experienced once. Age shows this above all. The experienced writer, no matter how experienced, cannot return to the past in order to write. There is nothing wrong with that, except if, out of an abundance of caution, he perceives in it an opportunity that has been lost.