I wanted to discuss an interesting debate that many job seekers have asked me... 
Do you have to include EVERY job you've worked in your resume?

 - Maybe you had a job that you started, found wasn't a good fit for you, and would prefer to just leave it off your resume because it was only 1 week of employment. 
 - Maybe you were fired.
 - Maybe you were working multiple jobs at once and don't want it to appear that you are a "job hopper" from first glance.
 - Maybe you don't want it to appear that you don't have a focused career path.
 - Maybe you just took a job temporarily until you found "the right job."

My response to this debate may ruffle a few feathers, but it's realistic, and is in your best interest.  Having worked in Human Resources and Recruiting for multiple companies in many types of environments, I've seen what goes on behind the scenes.

Keep in mind that, as a job seeker, your resume is essentially an advertisement for the purpose of selling your knowledge, skillset, and ability to perform. Therefore, it is up to you to determine which jobs to include in your resume to best market yourself. However, there are some important things to keep in mind:  
  • If you get an interview, the interviewer will probably have you walk them through your work history
  • Many companies have you complete an official application, which asks you to include your work history for the last 5 to 10 years, including every month & year that you left each employer
  • Over the years, it has become an unwritten expectation that you include EVERY job in your resume
  • Many interviewers and applications ask you to explain, in detail, reasons for even 1 month of a gap in employment
  • If you have had too many jobs in the last 5 to 10 years, you may be perceived as a "job hopper" (not loyal to a company)

Honesty is USUALLY, but not always the best policy.
Why do I say that?  Sometimes, people make mistakes in life and, also can experience negative circumstances outside of their control.  Heck, maybe you even did something blatantly wrong!  The bottom line is... You still need to feed your family and provide for yourself to live.

Employers are looking for problems in your background & work experience to determine if you pose as a risk to hire.  Gaps in employment can imply that you are trying to hide something:  jail-time, laziness, lack of drive, lack of desirability to other employers, that you were fired from a previous position, etc.
During the hiring process, large and medium-sized companies will many times will pay to access an online database that collects your work history, which is attached to your social security number, and has been submitted by many participating companies.  Therefore, in most cases, it is wise to be 100% honest if the question comes up during an interview or the application DIRECTLY states to include ALL and EVERY employer you've worked at during a certain period.  If the topic doesn't come up and it is not directly stated in the application, don't give away extra information that could hurt you.

It is a calculated risk that you would take, but if you feel it is beneficial to avoid disclosing a certain position, you may want to try it depending on your situation.  If the company runs an employment verification report on you and finds something you left off, be honest, and confidently remind the HR representative that a resume is "just an advertisement to showcase your ability to perform," that you didn't feel that position was relevant/significant, and that you were never directly asked to disclose it until now.  However, if the reason you left it off was because you were fired, you're probably out of luck and should be persistant in applying at other companies, especially smaller businesses.  Otherwise, you could always be upfront and honest about being fired.  If you do, try to gain a little sympathy from the interviewer saying you were going through a very difficult personal situation that has since been resolved, and definitely learned to never let a personal issue affect your work!  Then highlight positions with high performance, long-terms of employment, and offer an overwhelming number of positive references.  Even some large companies won't instantly reject you if you're upfront and honest about it, depending on the situation.  On the other side, some large companies have a company policy preventing candidates that have been involuntarily terminated in the last 7 years from being hired, unless you have court documents ruling an Unjustified Termination.