Development can be extremely financially rewarding, if you get it right. Through the process, however, you will be paying out to solicitors, finance companies (who first ask for a fee to lend you money!), planners, architects, building surveyors, monitoring surveyors, contractors, suppliers, the list goes on.
At the end of the process if you have successfully navigated the process and the market has been kind to you, you will receive a large return. However, this only happens after everyone else has been paid, the main one being your lender if you are using finance. So be prepared to wait and pay out along the way before you see any return!
