Unless you are an infrequent rider, experiencing pain or uncomfortable on your bike a good professional fitting is well worth the money. With the wealth of good solid info on the web and You Tube videos, it is possible to do your own bike fitting. However besides having a qualified bike fitter evaluate your position on the bike and make adjustment from a seasoned eye, they can make more accurate measurements. Also, it saves a lot of trial and error when new components may be involved. For example when I had my bike fitting done, I did most of it on my own right after getting my bike and I suspected to correct the one problem I was having, a shorter handlebar stem might be required. Sure enough the fitter recommended it and was able to get close to the size by using an adjustable stem, which put it in the ballpark. I was able to get the correct size stem there on the spot and left with a much better fitting bike. Had I replaced the stem on my own, it would have been a guessing game and likely require multiple trips to the LBS to get the right one.