One problem with not going below 500ft, is that you don't get to see the effect on your height of slowing from best glide speed to landing speed. It can save a lot of height, and wind up leaving you too high, unless it's a huge field.
Admitedly FD is right in saying that if you practice glide approaches at the airfield, you will get used to this, however many busy fields don't like people doing glide approaches in their busy circuit.
People seem to be favouring the constant approach method here. I was thought the square circuits method, and never shown a constant aspect approach. Would someone mind explaining exactly what a constant aspect approach is? I have a rough idea, but aren't too sure what exactly it is!
Thanks
dp