Frank slid his bow off his shoulder and propped it against the rail. “I think I should turn into a crow or something and fly around, keep an eye out for Roman eagles.”
“Why a crow?” Leo asked. “Man, if you can turn into a dragon, why don’t you just turn into a dragon every time? That’s the coolest.”
Frank’s face looked like it was being infused with cranberry juice. “That’s like asking why you don’t bench-press your maximum weight every time you lift. Because it’s hard, and you’d hurt yourself. Turning into a dragon isn’t easy.”
“Oh.” Leo nodded. “I wouldn’t know. I don’t lift weights.”

The Mark of Athena, Chapter X