In my field (economics), there are many co-authored papers. People are even writing some chapters of their PhD thesis with other colleagues.
I know that single-authored papers are more appreciated when you are a Ph.D. student and when you are in the job market.
Until now, I always prefered writing my papers alone. This is not because I did not want to interact with people but I did not really want to be dependant on other people during my Ph.D. (I know that some projects take so much time to be accomplished since everybody has its own research agenda.)
I wonder if writing papers (or chapters of a Ph.D. thesis) always alone is a bad sign on a CV? What are the advantages and disadvantages?