Custom software will generally produce the most efficient system as it can provide support for the specific needs of the business, which might not be available in an off-the-shelf solution and will provide greater efficiency or better customer service.
Given a suitable approach to development, such as DSDM, custom software will also produce the best or most well-targeted service improvement.
Businesses can tailor the software to what their customers want instead of having to choose a package that caters for a generic market. For example, one printing business may want software that responds in the shortest time, whereas another printing company may focus on producing the best results; as these two objectives often conflict, an off-the-shelf package will normally sit somewhere in the middle whereas with custom software each business can focus on their target audience.
Although not always the most suitable for larger or more complex projects, a spreadsheet allows less technical staff at a business to modify the software directly and get results faster. Custom software can be even more flexible than spreadsheets as it is constructed by software professionals that can implement functionality for a wide range of business needs.
Since custom software is developed for a single customer it can accommodate that customer's particular preferences and expectations, which may not be the case for commercial off-the-shelf software. Custom software may be developed in an iterative processes, allowing all nuances and possible hidden risks to be taken into account, including issues which were not mentioned in the original requirement specifications (which are, as a rule, never perfect). In particular, the first phase in the software development process may involve many departments, including marketing, engineering, research and development and general management.
Large companies commonly develop custom software for critical functions, including content management, inventory management, customer management, human resource management, or otherwise to fill the gaps present in existing software packages. In many cases, such software is legacy software, developed before commercial off the shelf software or free software packages offering the required functionality with an acceptable level of quality or functionality became available or widely known. For example, the BBC spent a great deal of money on a project to develop its own custom digital media production and management software, but the project experienced troubles, and after many years of development, was cancelled. A key stated reason for the project cancellation was that it had become clear that commercial off-the-shelf software existed that was, by that point, adequate to the BBC's needs and available for a small fraction of the price.
Custom software development is often considered expensive compared to off-the-shelf solutions or products. This can be true if one is speaking of typical challenges and typical solutions. However, it is not always true. In many cases, commercial off the shelf software requires customization to correctly support the buyer's operations. The cost and delay of commercial off the shelf software customization can even add up to the expense of developing custom software.
