Just did a quck check for my top preferred search term. In the early days, my site used to perform well for this, but with more & more competition, and also some neglect my side I did slide down a lot, from page 1 to page 5, but was still doing well for other phrases. Interestingly, I did do some SEO work on my site some months ago, and although there was an initial increase in the SERP, site soon dropped to it's more normal position.
Then today after reading this post I did another check and see that I am now No 3 having jumped up from say position 39 or so. Let's see how long this lasts.
Ironically enough, I do do SEO work for existing clients, and in general achieve very good results, but it was with my own site I was having problems!