It really doesn't take much to knock an alignment out of spec. That being said, you may or may not actually need it. Does the car visibly look like it is out of spec? Does the car feel like it's behaving differently than it used to? Is the car tracking on the road? Are you getting uneven tire wear? These are a few questions you can ask yourself to help determine if you really need it or not. You may not necessarily be able to tell just by looking at it though and you may not be able to feel the difference if the alignment is off. The only way to know for sure if it is off is to check the specs on an alignment rack or with the proper tools.