There are no years off from life, but maybe a break in a relentless path to a career is a good idea. It depends on what you want to get out of it. You might have been away from home too long and want to go back and watch your younger siblings shine in high school athletics. You might have a family member that needs a little care from you. You might want to learn your family recipes more carefully. There are lots of good reasons for going home for a year before continuing your education in graduate school, med school, or some other professional program.
On the other hand, you might want to stay at your university and finish up a research project, or be sure a community endeavor you started as a student flourishes. You might have very close friends that did not graduate yet that you want more time with. Some students stay in the city where they graduated for another year or two.
Perhaps most exciting is the plan that takes you out of your country to explore another system. You might want to go live in Ecuador or Brazil or Kazakhstan, though you are likely to be limited to 3 month tourist visas unless you plan carefully.
More and more students are taking a year off before college, after college and before grad school or professional school. I think it should be a time for reflection, time for yourself and time to make a difference. It might allow you to focus on that important task of getting to know yourself better. It could be a period where you change your mind about your career path. We have so many options these days and different ones suit different people.
Whatever you do in your gap year, it is an important time to push your boundaries by learning something you are new to, a language, how to use a camera professionally, how to tutor needy students, or any of the myriad possibilities out there. Give yourself to something that matters, climate change, immigration, health care for the needy, education of many kinds. Find out what works for you. There are lots of sites with information for temporary positions. Texas A & M runs an excellent site for environmental positions. Browse the internet and you will find others, like this one. Some students spend several years helping out on field projects.
How can you go wrong with a gap year? I would say it is by doing something nearly exactly like what you think you might want to do for a career but without the pressure, without the advancement, and without the discovery. If you take such a position at the end of the year you may not have grown. You may not know yourself any better. You may just be in a predictable rut.
This may not be fair, but one example that seems to be a poor use of a gap year for someone thinking of medical school is to be a medical scribe. From what I have heard from students who do this in hopes of increasing their chances of getting into medical school, it is neither educational nor adventurous and may only show you the boring side of being a physician. It might even be a kind of exploitation of a bright young person. Why not instead go somewhere where you can help more, perhaps a health clinic in another country, or somewhere you can use your language skills to help people?
We don’t get gap years in life, though we do get sabbaticals in many jobs. So think hard about what you want to achieve. Keep a journal. If you want to learn family recipes or stories, write them down. If you care for a family member, learn their past. Have fun! But also remember there is nothing wrong with plunging right into the next step. I did, though none of my children did.