Most renovation or new building project budgets are determined by the way you approach your project. Your approach to the project may fall into any one of the following: Investment Project Approach This approach to determine your project budget is concerned with maximizing the rental return of an investment property. It may also be concerned with achieving long term capital growth, and ongoing running and maintenance costs. Development Project Approach This approach to determine your project budget is concerned with the resale of your project after completion. The design brief is formulated and costed to achieve this profit. Affordability Approach.