How often should a person visit an eye doctor?

Anyone with a history of visual problems should get routine preventive care.

 People who wear contact lenses should get an exam annually.

An exam every two years is sufficient for adults in their mid-twenties to mid-thirties.

Yearly exams become important in the late thirties when changes in vision and focus along with eye diseases are more likely to develop.

Squinting, blinking, rubbing eyes frequently, headaches, changes in vision and difficulty with visual concentration within arm's length may be signs of eye problems and should be checked by your optometrist.

http://www.uhs.umich.edu/depts/eye_clinic.html#checked

http://en.wikipedia.org/wiki/Eye_examination

It is imperative that people who have a family history of eye disease such as age related macular degeneration (AMD) visit an eyecare professional for annual eye exams.  Early detection is imperative for such diseases.

While some people say every two years, remember, your vision is the number one sense ... do not take it  for granted.