Hello forum developers, I met some builder developers and armchair developers recently and they said the ROI is around 10-25% for their little projects. It's not bad at all but as the one coordinate to deliver some projects with 50-60% ROI, I found that they could get better figure if follow the shark. The key is design and contract management. It's always wise to spend best money for DA, but the rest would be put in extreme cost saving control. Forget about fancy shape building or decoration that overexcited architect proposed, the design and documentation only serve for ease building works, splitting into multiple micro tender packages so suppliers and subcontractors fight for smaller cake with generous discount. It's also good to know how to control the specs and its alternative options. Generally, architect or drafties prepare the tender in single whole package for their convenience hence eliminating all cost saving option in construction stages. So you'll need a good practical architect and a well contract nego skill then the ROI will be boosted 10-20% more than usual. It works extremely well with large development and may be worth considering for your next project.