Another aspect which is often missed during thinking about own number, or discussing the offer with a recruiter is that even if one's skillset is worth X, it is

Another aspect which is often missed during thinking about own number, or discussing the offer with a recruiter is that even if one's skillset is worth X, it is not always the case company will need the whole set of skills applicant posses. Hence their market price for that position might be lower than what an applicant is looking for, yet still fair. This kind of mismatch of honest numbers is the case where things will just not work out. One thing is being underpaid, the totally different thing is doing something too simple for one. When I was searching for a job, I used to ask straight their salary range, since I always assumed business is pricing job fairly and that number would tell me what kind of skillset their business need. (And no, one's extra skills are not gonna give an edge to business, and usually these extras worth nothing to the business, hence lower offer)