The configuration file is big. There are many parameters. If you make customizations, it can be difficult to find them or remember why you changed the values. To avoid confusion, add your customizations to the end of the file in a section you create for that purpose. For example, you can create a comment line with the following text: ! My ics.conf Changes. Then add any new parameters or any parameters that you are modifying, and their values. Add comments to each parameter describing why the change was made, with the current date. This will give you a history of the changes made to the system for later reference.
Every time you start or restart Calendar Server, the system reads the entire configuration file. The more parameters the system must process, the longer it takes to start up the system. If there are many duplicate parameters, it can slow the process noticeably. To avoid this, comment out obsolete duplicate parameters.