I agree and disagree with Andy.
If a lifter is well balanced, ie core strength, quads and PC equally strong, then all he needs to really do is squat. This lifter will ideally have great leverages as well, not long shins etc.
these lifters, while not rare, are not the only kind that like to squat. I quite often get a lifter who has done no PC work, he is quad dominant and his PC gets no stimulation while squatting.
Thinking he will improve his squat simply by squatting is idiotic by definition.
The more common ailment I get though is the Accordian squatter, he literally folds in half as he descends.
Surely no one on here thinks that all this guy needs to do to improve his squat is squat.
I dont even allow these guys to squat at PTC, well not back squats anyway.