I recommend checking the wheel alignment at least once every two years or at every second oil change.
However, if you hear the tires squealing loudly, even when driving slowly, you might want to visit the service shop sooner. That is particularly true if you've hit a significant pothole or curb or had another jarring road experience. Such impacts can throw off the alignment settings.
While alignment checks can help prevent squealing, they're also essential for overall vehicle health and safety, which makes frequent checks all the more important.