In some scenario, it can be intersting to launch another Visual Studio with a different configuration. For example if you use more than one kind of source control, it can be very boring to change source control and provide authentication in each time you want to develop.
In other terms launching Visual Studio with different configuration offer a ability to customise your IDE according what you need in a specific scenario. Black theme at night & White theme in daylight, advanced debug configuration when debuging something hard, etc…
There is already a built-in alternative instance called Experimental Hive used to develop extension for Visual Studio. I recommand to not use it for another need because it is very slow comparing to custom instance. Indeed is is not a simple custom instance but a special instance.
How to create and identify a custom instance
Copy your shortcut to your Visual Studio and change the target program
Pass to Visual Studio (devenv.exe) the following arguments : /RootSuffix [MyCustomName]
Example : if you want a custom instance called : MyCustomConfig
enter the following line as target of your shortcut :
...\Common7\IDE\devenv.exe" /RootSuffix MyCustomConfig
Save the shortcut and launch it. You can now configure your new custom instance. Each time you need to run this instance, just launch the shortcut.
You can create as much as one wishes!
Visual Studio have the ability to run multiple instance with different configuration that can be useful to manage different view, plugin, history, fonts, source control, etc.. that allow a better organisation if you work on multiple project with different condition/environnement.