Add variation. That doesn't mean squat less, just squat differently.
If you've been doing nothing but 5x5, do sets of 10, or triples, or doubles, or singles. If you've been slogging away at low intensities, ramp it up for a while. If you've been doing nothing but low-bar wide stance squats to parallel, how about trying some good old-fashioned front squats for a while? If you always use compensatory acceleration, how about trying to slow it down? If you always squat slow and controlled, how about adding some chains and acceleration? If you only do barbell squats, how would squats with kettlebells or a heavy sandbag go?
Embrace change. Embrace growth.
"The oldest habit in the world for resisting change is to complain that unless the remedy to the disease should be universally applied it should not be applied at all. But you must start somewhere."
- Winston Churchill (on squat training)