Hiring managers with ageist biases may see older job seekers as having a tough time keeping up with younger job seekers when it comes to technology and new advancements.
In addition, it may be a belief that an older job seeker's experience is outdated, especially when an employer is given a choice to hire a younger worker, who will likely have more updated and relevant skills, certifications, or requirements.
Using dates can be a huge mistake. Don’t use dates for college, advanced-level degrees, high school, or any certifications, or professional development courses. You may want to consider removing high school altogether if you have a college degree.
Just stating that you have 20 years of experience – or more can flag you as an older job seeker. You can typically limit experience by two things – years and length of the resume.
Whatever resume format you choose, it would be a mistake to be shy about your skills. Show potential employers that you know the latest technology or software. Also, remove any old or outdated technology.
Targeting on the position you're applying for focuses your resume on your relevant experience, accomplishments, and skillsets. Failing to do so is a mistake.