Giving estimates for software development is a dark art. There is no question about it. Software is hard and variable. To estimate software accurately is like trying to give an accurate weather forecast for two months from now.Fixed bids are simply detrimental for business as they breed bad products. A fixed bid is a contractual agreement to provide a product for a pre-determined price or price range. No two applications are the same and each require specific development and design to create your specific application.