I always wear a seat belt. In my own car or any other I ride in. Have since I started driving in 1965.
Used to be difficult in the 1960s. My friends would bury the belts, which had been recently introduced in new cars (just the lap style, we didn't have 3-point shoulder belts yet) down between the seat backs & cushions out of sight.
"Don't pull those out!" they'd yell at me. "I don't wanna see those things!"
"I'll shove them back out of sight when I get out of the car." There weren't laws yet mandating their use, nor bells and instrument panel alerts if you didn't have the front ones buckled. I still wore mine.
One time my wife lost control of our minivan when she sneezed and went into an Interstate guardrail at around 65 mph. She, our 5-year-old son, and me were belted. The 1-year-old baby was in a properly secured rear-facing child seat. None of us was seriously hurt, and the baby had no injuries at all. Our 1990 minivan had no airbags.
But the 3 of us had bruises from the belts, the impact was so great. And the driver's seat back was all bent. Yeah, I wear seat belts in any vehicle I use that has them.
Some of our friends will have their rear seat belts inaccessible, caught in the fold-down seats of their SUVs. "Don't bother with that," they'll tell me, "We're just going 3 miles."
Ah, no. I unlatch the seat back and free the belt to use it. Most car accidents happen within a few miles of home. I'm gonna live to see another day, and not from a hospital bed.