1. If you have gaps in your work experience for various reasons you might want to put a job that you did 12 years ago under your job experience especially, when the job you did is comparable to the job that you are applying for.
2. Another reason is if you have a side business or job and have been doing it a long time you might want that in your experience section to show that you are competent and have other experience, especially if this experience can help you get the job.
3. Another reason would be if you had been caring for a loved one such as mom, dad, sibling, grand parent etc, and were not working for a certain amount of time, you can explain that gap by putting it down as a caregiver and
put down dates you were caring for them, and that would explain some of the working experience gaps and explain all the duties that you did as a caregiver.
4. Another reason is if you had gone back to school or worked on an internship for a couple of years, and you learned many things and got experience with the internship those might be reasons to go back a few years before the school or internship especially if it is pertaining to the jobs you are looking for. and explain what you
did on that internship or job.
5. There is one other way you can set up your resume: Under the Experience Section you can also have a Previous Experience Section: This gives the reader a chance to see what other jobs you have done. I would not really advise this unless you don't have enough experience under the experience section. At least two or three jobs to show the reader you might be a good candidate.
I hope this helps. A book on resumes will help answer some questions. I hope I understood correctly what you wanted to know, and please let me know if you have any other questions. I wish you the best!!
In my professional experience, a good resume should be no longer than 2 pages. Professional experience, or employment should reflect the last 10 years. Use key words and bullet points to highlight experience. There are many free templates on products such as Microsoft Word, or the internet that can help you write an effective CV. I hope this helps.