Ask HN: What part of job search is most difficult for software engineers?

I am about 50% finished with a book of job search advice written specifically for software engineers and technology professionals. This is the first of a planned series, and this initial book will focus on the job search process from before you start the job search through the transition to a new position. What elements of the job search do you find most difficult or challenging? In my 15 years as a recruiter of engineers I've counseled thousands of candidates, and many were unprepared for various elements of the search process. (NOTE: I'm well aware of HN's feelings about recruiters, and a fair portion of my book is intended to expose some of the industry's secrets and motivations, as I believe this transparency will allow engineers to make more informed decisions when working with recruiters. I've written articles posted here on my thoughts on recruiting as a whole. A page with details on the book release and a sign-up form for a free chapter can be found at jobtipsforgeeks.com/book)