Why optimize your web site?
Success is biased at being top of the rankings. The top-ranked site for a search does better than #2, and the top few get many times more visits than the results at the bottom of the first page, which in turn get many times more clicks than results on page 2 etc. etc.
The skew is so great that the benefits of getting higher up the rankings far outweighs the costs. You should be optimising your web sites to get high rankings.
Aim to get in the top 5 or 10 results for one or more specific search terms.