Tire alignment seems to be one of those repairs that sneak up on you. Unless you're really focused on your tires, you can easily forget about alignment until you find you need new tires early. There are ways to tell ahead of time, however, so keep an eye and ear out for these signs -- and learn which other "signs" you can ignore.
The Signs to Look For
When your wheels are out of alignment, you'll notice the car actively pulling to one side. You might not have to fight much to keep the car heading straight, but you'll see that the steering wheel appears to be tilted instead of centered as you'd expect when trying to drive straight ahead.
Something else you should watch out for is the sound of a squealing tire when you're not driving aggressively. You've no doubt heard the sound of tires squealing when someone speeds off in a car chase in the movies. However, if you hear tires squealing when you make a tight turn, for example, even when you're not speeding, you may want to have your alignment checked. Uneven wear can create squeal-like sounds.
Of course, the big clue is tread wear. Learn how to spot uneven wear on your tires and bring the car in if you see any. Misaligned wheels create uneven treads that can make the tires wear out more quickly than expected.
The Signs That Don't Matter
The advice to find a straight, level road and drive with your hands off the steering wheel does not really help you know whether your tires and wheels need an alignment. It's a good concept, but roads are usually graded with a slight dip toward the edges to ensure water runs off to the side when it rains. If you try driving with your hands off the steering wheel, you'll likely see a slight pull to one side anyway just from that grade. You can certainly try it, but don't assume every little movement to one side or the other indicates a need for alignment.
The Signs That Indicate Something Else
If your steering wheel shakes while you drive, that's potentially related to your wheels, but it's not the alignment. A steering wheel shaking when you brake indicates a brake or strut problem. A steering wheel shaking when you're driving at highway speeds (generally over 60-65 miles per hour) indicates your wheels need to be balanced, which is a different procedure than alignment.
Bring your car in for a wheel alignment service on a regular basis, especially if you live in an area where you have a lot of potholes. Keeping the wheels in alignment helps preserve your tires and your car repair budget.