I was always self fit using Peter White's suggestions as well as any other wisdom found on the internet. I only ever had one problem - a soreness above my knees that was solved by running shorter crank arms. I changed to 172.5 and that problem was solved. Quite by chance a friend who works at an LBS offered to fit me for free, after he had returned from a fit class offered by one of his bike vendors. The fit wasn't super technical with computers and stuff, just some measurements and flexibility testing. What I came away with was a much more comfortable ride, some added power and gained knowledge. My saddle was too high, my stem was too long and I wasn't using nearly enough bar drop for my level of flexibility. With this information I'll be getting a new -smaller - frame that allows for more bar drop and going back to have it fit as well.

While you may be able to self-fit your bike to within a certain degree of comfort it is super helpful to have someone more experienced and even trained in fit to really dial it in. While I used to think pay-for-fit was mostly voodoo I am now sold.

my $.02