With Synology's Time Backup App on DSM 4.0 you can accomplish a simple backup solution that can be setup to run at times and dates of your choosing. From a Monthly backup to an hourly backup, it's your choice.

This can also be a simple solution for file overwriting for those that are not utilizing subversion or checking files out, at least for a smaller team. 

With Time Backup you can intuitively browse, or slide among versions.

Then easily restore old file versions with a right click.