I had Three instructors (the club's full time compliment) and all of them taught me different and valuable things, Some had a more rigourous professional method of flying which passed on good habits (being AT altitude and AT speed not +/-) and some had highly valuable prictical advice, not just about flying the A/C but practical local weather knowlege and handling tips.
As for Spinning before the circuit?? what? we covered advanced stalls (as in stalling in the landing config) before going into the cuircuit, but i'm sure we didn't cover stuff like spinning or wing drops until later?
As for knowing when your ready, at some point you'll find yourself going downwind and saying "ho Hum this is taking a while" you've nailed your height, trimmed and are on approach speed and finished your checks.
I remember i was porposing around busy doing my checks and downwind calls i'd look up (yes i know- head out the cockpit plse) and it would be time to lower flap and turn base. there never seemed to be enough time!!!
As for the flare.... gotta love tommie undercarriages... stronger than diamonds!