Shipping is the start, not the end. Software needs occasional care: dependencies update, requirements shift and small issues surface in real use.
Maintenance is offered as an optional arrangement after delivery and can cover:
- Security and dependency updates.
- Uptime monitoring and prompt fixes when something breaks.
- Small enhancements and tweaks as your needs change.
- Hosting management, if your project runs on managed infrastructure.
You are never required to take a maintenance plan; because you own the code, you are free to maintain it yourself or hire anyone else. Many clients prefer to keep the original developer on call simply because it is faster.