Since cell changes may occur before any symptoms of cancer show up, this underlines why Pap smears are important. Some people have said a woman doesn't need one every year, but I disagree. I can, in fact, make a better case for this than a yearly mammogram, especially in women who do not have a family history of breast cancer.
Pap smears rarely show false positives (or false negatives, for that matter) and they do not expose a woman to anything more than about 30 seconds of minor discomfort (assuming the doctor knows what he or she is doing). No radiation or X-rays are involved. Just a quick swipe and you're done.
And, the earlier any abnormal cells are detected, the better the outcome usually is. Having a Pap smear is not my favorite activity, but I'd rather do that than be diagnosed with Grade 4 cervical cancer.