Should I give up?

Every once in a while, I'll read about indie authors considering quitting because their books aren't selling. In some cases, I think it's just a case of unrealistic expectations. IMHO, any author who has just published a first novel and wonders why it hasn't sold a thousand copies in the first week is delusional. On the other hand, there are also authors with multiple books that have been available for years, and their books still aren't selling. Should they quit? That's a tougher question.

I...