Flyboy makes an excellent point and one which is unfortunately seems all too common. People get into the habit of turning crosswind, base, final, etc at landmarks rather than from visual clues either from the aircrafts instruments or from the runway perspective from the cockpit - the upshot being that when they venture away from their homebase or to a different type of airfield they make a complete hash of it!
I have to say I have never had to level off on the runway at 500' for traffic whilst flying circuits and recommence the climbout later on. I have always used 300' T&Ps, 500' throttle/manifold pressure reduction, 700' turn crosswind, 1000' S&L. On IFR climbouts I have always been given the altitude to turn at in the clearance, i.e. 'Fly runway heading until 800' then left turn to heading 200', vectors for.....'