Small investment for a lifetime of knowledge.
My first helmet I bought was a Scorpion EXO-R2000. I thought it fit me well but a much more experienced friend pointed out to me that I had too much open space near the temples and actually taught me about the "roll-off" test and proceeded to tug the chin bar downwards and the helmet went over my eyes. This is not supposed to happen if the helmet actually fits you correctly. In hindsight, I thought about how there seemed to be extra pressure on my forehead as opposed to the sides. Feeling bummed that I spent hundreds of dollars on a helmet that didn't fit me correctly, I sought to learn more about how helmets should properly fit, as well as a new potential helmet that would fit better.
This search brought me to lidpicker. The particular helmet that I wanted was the new Bell Race Star Flex DLX, but there were none for me to physically try on at my local CycleGear. After researching lidpicker more and seeing good reviews, I decided to try it myself. Bought the $25 kit, measured my head, submitted the results, and eagerly awaited. The next business day I got my results. Based on my measurements, the results showed that the Scorpion EXO-R2000 was out of range and too round for my head, which mirrored exactly my real life experience. I found the Bell Star Flex DLX in the data sheet and lo and behold, the helmet that I wanted was showing that it was ideal for my head!
I proceeded to order my new Bell online and once it arrived, I tried it on and for the first time I experienced what a proper fitting helmet should feel like. The small investment I made in lidpicker has informed me for a lifetime. Even if the helmet you want isn't on the list (which has a wide array of the most popular helmets regardless), you can use the existing information to try on helmets that are on the list and understand how a good helmet should fit. On top of that, if you have any additional questions, customer service is prompt and very helpful. This service is well worth it!