Some years ago whilst conducting Flying Scolarships I had to send 10 students on their first solos over a 2 day period. Each student had been trained by a single instructior, but as we had 3 assistant instructors, they could not authorise fitst solos. I planned to fly a single sortie with each student before sending them solo. It became quite apparent how different their instruction had been and individual instructor characteristics showed themselves in the way the students performed. This brought it home to me that a little bit of exposure to another instructor is not a bad thing.
More recently I have had to sort out a number of student who were spending a lot of time in the circuit and not getting near to solo. The cause was the same in all cases, poor coverage of early exercises, into the circuit too soon with instructors who clearly tried to teach everything in the circuit.
Standardisation in flying clubs is difficult to acheive. Recenty a club member stated he had flown with his grandson who was learning to fly, it appeared he arrived at the airfield and was collected from the gate and taken straight to the aircraft, he flew a sortie and was taken back to the gate. No briefing, no debriefing, no use of radio, and no exposure to any planning materal. Maybe the result of Covid, but a clear indication the school were only interested in income from aircraft hire.