They way that I ws taught to fly a pattern was turn crosswind at 500ft AGL, then make the downwind turn (regardless of height - two fairly large fella's in a 152 means that there is no way to be at circuit height at the turn onto downwind leg) with the end of the runway at about 45deg, and do the same turning onto base leg. I find that if I can stick with this it makes for a neat circuit.
If someone else extends the circuit, and it is feasible to slow down, then I do so and try and get the circuit back to a "normal" one. If this is not possible, then I live with it until the tower starts to make everyone tighten up.