It is much easier to update your resume periodically than all at once, so even when you’re employed, set a reminder to refresh your resume every three months, while the information is still fresh in your head. This will make your next job search much easier, should you decide to switch companies or careers in the future.
If you have major gaps in employment, there are a few ways to make them less noticeable like a change of resume foramt. It is important to be honest about gaps in your resume and not try to cover them up, but to also make them seem productive and intentional. Adding volunteer work or classes in the time you were unemployed is highly valuable and fairly simple to get starter with.