If you live in a warm-weather state, there are fewer ways to misalign your vehicle suddenly. You have to hit a curb or something else fairly hard. Unfortunately, we live in a state that's only warm part of the year so there are plenty of "something elses" around at times. They're called potholes and they range from the "little-bump" variety to the occasional "jolt-awakes." I discount as rumors the swallow-your-vehicle-in-a-single-gulp potholes, even though a couple have starred in Hollywood movies.
Whatever causes a vehicle to be misaligned, the effects show up in poorer handling, shorter tire life and wasted fuel. But the most important reason to keep your wheels aligned is safety. Worn tires that poor alignment can cause, provide less traction in skids and on wet or slippery roads, and don't perform as well as good tires in emergency driving maneuvers.
Because of our annual pothole season, we have a problem knowing when to get an alignment. Auto manufacturers recommend alignment (and wheel balancing) about once a year. Because a pothole can immediately put a recently aligned vehicle out of whack again, you might consider, if your last alignment was nearly a year ago, waiting until most potholes have been filled.
But if you notice any of the following, have your alignment checked no matter when it was looked at last:
Your steering wheel "pulls" or "drifts" right or left when you're driving straight on a level road;
Your steering wheel isn't centered when your vehicle moves straight ahead;
You notice uneven, excessive or rapid tire wear, especially tread that's deeper on one side or that feels smooth in one direction but jagged in the other.
If there's vibration in your steering wheel, usually at 50-70 mph, or a "loose" feeling in the steering, you probably have one or more wheels that need balancing. Getting that done with an alignment saves you time.