For those of you that don't really know that much about cars (like me), wheel alignment is a modification that your local auto shop can do for you. It consists of calibrating your tires so that way when you drive, they don't wobble to the left or tilt to the right... unless you steer it, of course. When wheels are properly aligned, it allows the driver to have better control when steering & permits the tires to wear evenly. If wheels aren't aligned right, then you might have some major problems on your hands.
Wheel alignment can be easily affected. Say you're driving a little too carelessly, you hit a curb & then you damage your brand new 2008 Toyota Camry Wheels ; or you hit one of those pieces of cement that's put in front of you in some parking lots; that can easily make your alignment a little off. Once you accidentally hit one of those objects while you're driving, the orientation of your wheel can become somewhat off-center. If you're a typical person like me who doesn't really take the time to observe if a little bump messed up the alignment or not, I won't be able to tell with my naked eye; but if I take it to a tire shop or a regular auto body store, they'll most likely be able to tell pretty soon-sooner than you at least.
If a wheel happens to be "unaligned", you'd be able to tell pretty soon. The tire that's off-center is the one that's making your car slant to the right or the left. Let me give you an example, if I was making a right turn at a stop sign & my right front tire hit the curb, then when I drive on the freeway, my car would be slanting the the left because the wheel was pushed to the left. I'd have to constantly sustain a right-pull on the steering wheel since it'd be drifting to the left. If I don't fix it as soon as I notice it, it'd cause for the tire to wear faster than the other ones & have a HUGE repercussion on my gas mileage. I have a V6 Toyota 4 Runner so you know I'm going to be worried about my gas.
When a tire shop notices that the tread wear is uneven, they can tell that you've been driving your car for a while without fixing the alignment. Most of the time, the innermost part of the tire tread will become smooth & there'd be an abundant amount of tread left on the external part, or the other way around. If this happens, you're tires would probably last for a shorter amount of time & you may have to spend more money to replace that tire.
If you're completely worried that you may have to get your wheels aligned, no worries; it should take about an hour, if not less. When you get this done, the price usually covers the rotation of your wheel; which should help your tires wear evenly... unless you're going to hit another curb or something. If you have a Four-Wheel drive vehicle, the shop may want to rotate all four tires even if you just need your front ones fixed. You may want to start calling for quotes, how long it usually takes, & if they rotate all four tires on your car, or just the front ones.