'Flying a circuit' is a minor part of flying in general. You need to know much, much more than that. And a good, experienced instructor can teach a lot of that even in the circuit, while one with only a few hundred hours, most of it in the circuit, may not know much more than the circuit. At 500 hours, you're still learning to fly. Make no mistake, experience counts.
I remember training in TH-55's, lo those many long years ago, doing autorotations, mostly 180's, & when I thought I had them down, my instructor would take the controls & say "Let me try one". He'd do the entire pattern (circuit), 180 auto to touchdown, pick it up & hover off the lane, without touching the cyclic with his hand except to roll the throttle off & back on, talking all the time. Flew the whole thing with his knees. Taught me humility, how to do an auto, & ambition to get better all at the same time.