I'm thinking I could get away with not writing any more articles and writing only books from now on. My justification is that articles are a distraction. They either form part of the book project, in which case they are redundant, or else they don't, in which case they take away from the big enchilada. My reasons for writing articles are these:
1) I get asked to. I don't want to disappoint the person asking me, or not figure among the list of people in the special issue or book.
2) A book takes a long time to come out. Articles can be faster. I need to show yearly activity in research, but articles fill in the gaps and make me look busier.
3) Sometimes I have an article-length idea that doesn't fit into my current book projects.
4) Sometimes it is helpful to write things up in different forms before the finished chapter.
Only the third of these reasons is really a good one. The others are just forms of insecurity, being left out of the party, or fearing that my colleagues will think I'm a slacker (they won't). Since raises are minimal anyway, and research is always going to be my strong area, I could probably get away with no articles for the foreseeable future.
Of course, once I say this, I will probably decide to write another article. At once point I decided to write only articles from now on, no more books, and the result was the publication of two books three years later.