I am very familiar with Olympic lifters. No offense to my PL'ing buds but I think Olympic lifters are the true athlete's of the lifting game. If nothing else, Olympic lifting is a sport of skill, flexibility, timing and quickness. Sure do admire PL'ers who can move huge weight for short distance. But I respect anyone much more who can clean a huge weight from the floor and jerk it fully overhead, at a much greater distance, and lock it out for a few seconds. That would also include lifting huge weight overhead in one fluid motion, like in the snatch. I would think that it would be a personal insult to any true lifter to even suggest that a spotter would ever be needed.
Squating, either front, Olympic style, overhead or squat cleans (try either overhead squating or deep squat cleans for 12 reps, with a medium weight, and tell us all how you feel afterwards), are trained for stamina and power. Generally reps are never near their true max when training on a lift.They are training for the full function of that lift it's self. Form tends to draw strength to a lift when that is done. But they do have certain days in their train protocol when heavier squats are attempted. I heard some of them call that fun day. Also very big on front rack squats, while getting many reps in. And never a spotter in sight.
I have been told by older lifters, and have read, that some of the former Eastern block nations lifters like Bulgarian and Romanian's were renown for walking off the street (still in street clothes-with no warm-ups) getting under 500lbs or so, and knocking off a few quick reps of bottom out squats. To improve their function of squating, more squating at any weight was done. So if they passed a loaded bar on a rack , no matter the weight, they would get in some quick reps with it. (At that time all the spotters were on welfare because of no work for them to do.) Good Luck.