Without proper CI/CD workflow jobs, errors are easily made without noticing it (or noticed too late). Especially when multiple developers are contributing towards your code base. Maybe your project is open-source?
When developing in a (large) piece of software, automated building & testing are crucial aspects to avoid regression impact of the code archive and even deployment.
The latest best practices are to setup a good and stable continues integration. Ideally also add a continues delivery setup for your project. Meaning that each pull request you receive will automatically try to build, test and deploy the code.
With testing I mean unit testing, functional tests, integration and E2E tests. And maybe UI tests if your application has a frontend as well.
Personally, I use GitLab for all my own projects, GitLab has a great CI/CD pipeline feature built-in their software. I'm running multiple GitLab runners, ready to pick-up requests. Which could be a unit-test running a Docker container, software build using GCC compiler or deploying my code live towards dev, acc and production.
Lacking such a well thought out CI/CD pipeline might result is build issues, regression issues or in the worst case down-time or unhappy users. Try to avoid this by using CI/CD for each of your open-source projects.
Have fun programming!