If you are an Alfresco developer, you have to develop projects using Alfresco AMP modules. Previously Alfresco has used Ant to build projects. But latest Alfresco SDK is using Apache Maven. AMP maven projects generates whole lot of temporary files. Those files you don't want in your version control system.
Nowadays almost everyone is using Git. If I say Git is the most popular version control system today, I hope a lot of people would agree on that. In Git you can use .gitignore file to mention what are the files that should not add to the repository. So if you mention the patterns on .gitignore, Git won't commit unwanted files. For that you need a good .gitignore file. Last year I wrote a blog post which has almost all the file patterns which you should emit from Java project.
You can create a file called .gitignore on root folder of your Git repository. Then copy above content and add it to that file. After that commit that file into your Git repository. Now you don't have to worry about unwanted files.