When a project is completed, it's very easy to forget about it, and jump to the next project, but in order to deliver the best value to your customers, regular maintenance and improvements should be planned from the start to ensure a successful project both short-term and long term.
The maintenance phase is neglected by many, but in a modern web project, the maintenance phase is an important part of making the project a success for your customer. In complex projects, there are always things that need to be adjusted and improved after it has been launched. Assumptions made during the project sometimes turns out to be false.
A complex website will also require constant improvements. Set aside resources so you can handle such work quickly after a request comes from your customer. This is also important to retain a good client relationship.