I work in the industry with lots of large multidisciplinary property companies who have lots and lots of smaller contractors on the books who they use to complete work. Some contractual work is done via Schedule of rates with agreed discounts on the rates and or agreed increases depending on market trends with regards to supply and demand. Currently there is a shortage of skilled construction workers because a large proportion of them where from eastern Europe and they all went home after the brexit vote (not all of them of course but you try and get laborers for construction jobs in London and its a lot harder that it was 12 months ago). Over the last 10 years of so there has been an industry wide lack of training in lots of the `tool` trades which means as the older generation of these workers retire there will be a shortage until we can replace them. If you are good at a trade I would charge what you feel is a good rate, don`t overcharge, do a good clean neat job and build a reputation for doing exactly that. In my experience good `tools` people who are good don`t spend a lot of time on the tools, they get recognized by the companies they work for and promoted to surveyor so they can go out and price up jobs for the apprentice that they spent 3 years training to do... If I was on the tools right now I know what I would be doing.