It depends on who you are and what your goals are. If you're a powerlifter squatting heavy on a regular basis then yes, get some wraps. I have a feeling if that was the case, you would have already been using them.
If you're not a powerlifter, unless you can squat over 4 plates then you don't need them. Unless you're squatting heavy, you're knees aren't under much strain. That is, as long as you use good form.
Wraps will also allow you to do slightly more weight, which I'm pretty sure is the main reason most people use them.