My first vintage road bike - a Schwinn Le Tour III - was too big for me at 25", but I didn't know it. I'm 5'10" and had some nice rides on it.
I'm pretty adaptable with size, depending on distance. My smallest roadie is a 55cm. I love riding it. My Moto Grand Jubile is a 23" and it's nice and comfortable. I don't really care for longer top tubes and long stems. Had a Puch Bergmeister years back in a size that seemed right for me, but the top tube was too long. The range of sizes I have work well for me.