How Early Should I Book?

I am not getting married for another 2yrs (still in school and saving every penny). I have visited websites to get some ideas about what I like (I actually got laughed at when a videographer called meand I told him my date). How soon should I look to hire a photographer and videographer? I don`t want to wait for another year, but I don`t want to be laughed at because it is so far away. And I know technology will have advanced in 2yrs. Any help is appreciated.