It depends what line of business you are in and how seasoned or "good" at your job you are and that can all be contributed to your work history and your resume.
If you have a Sixsigma Blackbelt, an MBA, well versed in SAP and Oracle and 10 serious of Project Management under your belt with references to not only back up your work history but also to speak on your behalf of the quality of your work....you can pretty much demand whatever the competitive salary is for the position you applied for. It's these people who look at salary.com and use it as a tool to see what they are worth in different areas of the country.
The more impressive your resume the less likely you are in getting the apex of a salary or the job in general.
If you have no college education, a spotty work history (not fired but 1 yr here, 1 yr there etc..), no professional references from supervisors, no certifications in the field, no awards etc...you're lucky to get the job in the first place and have little room to negotiate.
Usually people will bring you in even if your expectations are a little high based on lack of substance in your resume. If a recruiter looks at your resume and alone thinks you have over priced yourself they will try to bring you in at a lower salary. That is their job, they're in the profession of judging worth based on resumes etc...
Then sometimes they will bring you in and interview you to see if the "worth" is there. If not...they either offer you what they think you're worth or you get a letter in the mail.
The best advice I can give anyone is to maintain a good employment history (just as important as a credit score), make sure you have a relationship with your supervisor so that if you ever do leave for whatever reason you know they will give you a proper reference. Never stop educating yourself, go back to school and get a degree for complete a certification program. Try and win awards at your current employer and volunteer for as many activiities as possible in order to add to your resume: training, mentoring, writing policy, leading seminars etc.....set yourself apart.
The more impressive your resume the more leverage you have with your current and future employers.