Personally I skim page one, then look at the adwords ads. If there is nothing there then I change the search by adding boolean options. I never go beyond page two, and rarely if ever leave page one. Only when I have been searching for some off the wall stuff when refurbing my house have I struggled.

Then again if an SEO doesn't know how to make a search engine deliver relevant results they should not be doing the job LOL. I get emails all the time asking me to find stuff online as average joe/jane can not get to grips with advanced operators.

I'll go in as far as page three if I have to because I search for all kinds of crazy crap.

If I don't find what i searched for on the first page I tend to change my search by changing the words, adding more words to make it more specific or use +/- quotes etc.

I would go to page 3 and beyond if i was looking for something obscure and didnt think I could make my search any more specific.