Using common components and patterns means you don’t have to solve problems that have already been solved. By using a component or pattern that’s already been extensively tested, you can provide users with a good experience in a cost effective way. If you develop your own components or patterns, share them under an appropriate open source licence so that others can benefit from your work. This avoids duplication of work and reduces costs for the government as a whole.
Open standards help services work consistently – so you’ll spend less time trying to make systems talk to each other. They also help in not getting locked into a particular supplier or technology – so when things change, you can more easily change your approach.