Doing SEO for clients pretty much means you go to school every day all over again.  The only mantra a “SEO GUY” needs is that “THINGS CHANGE”.

Not only do the search engines change how they look at websites, your competition changes how they do things.  The good news is that more and more businesses are waking up to the fact that SEO takes a long term approach.

It’s even making it into mainstream publications now:

From O’rielly, Website Optimization Book.

News Flash: SEO Competition Lengthens Campaigns
A few years ago, optimizing a site to rank high on search engines typically took four to six
months for reasonably specific keywords. Now it can take from 6 to 12 months for many
keyphrases to rank well because the Web has become more competitive.

And once you get to those top positions it doesn’t mean that you can rest on your laurels and do nothing.  You might be able to scale things down but you can’t just stop.