So I have a 15 year old DD. She has no curfew. But I do expect her to keep in touch with me e.g where she is, who she's with. Nearly every time she's at a friends house basically having a sleepover but without the staying over part. We live in a pretty safe village we rarely have a fight happen and if we do it's probably a verbal one where each person is around 20m away from each other so I'm not worried about her getting hurt. That and she's never home seriously late around after 12 when at a party and it's usually a lift from her best friends brother who tends to be a night owl but doesn't go out much so is fine giving them lifts late at night (it helps they only live 5 minutes down the road).
She's never broken any serious rules pretty much her whole life she's been a relatively good kid which is why I have these rules in place. I'd rather her be home at 12:30 having been sitting with a few friends in her best friends conservatory talking than home at 9:00 having been sitting on a street corner drinking a bottle of vodka