How Long Can I Keep My Capstone Project on My Resume?

When you have enough practical and real experience to remove it.

unless your capstone wins you a Nobel prize et al... than keep it on your resume...

Sure, keep the capstone project in there. And explain why in your cover letter. I can't stress enough, why a good cover letter is the most important part of your resume in your situation. After 11 years on active duty in the U.S. Army, I had no design experience either. What industry employers want to know in priority order is:

1) Do you play well with others?

2) Are you self-motivated? Are you willing to learn?

3) Can you effectively communicate in writing as well as orally?

4) What sort of experiences did you have in your previous jobs? Special skills or insights, leadership, community activities outside of work, any hobbies to show a breadth of experiences, well-rounded, etc.?

5) Did you graduate from an ABET-accredited post-secondary institution (college/university) meaning you have a good understanding of the basics in your field?

Everything else, you'll learn on the job.

From a company's point of view, the technical stuff is the easiest part.

I've never seen anyone fired or laid off because they couldn't do the technical work. It was always problems with 1) and 2) above. Layoffs are one way that companies use to trim away the 'dead wood' without going through the pain and work of firing/terminating the 'duds'.

Good luck with your quest.

After 30 years, what drops off the bottom of a 2-page <…Resumé…> is of little value to a prospective employer. It is what is pushing it towards the bottom that is of immediate interest.

Most prospects will spend less than 30 seconds reading them.