AFAIK, this will give you the directory where your exe file recides. I don't see that changing while your application is running (unless I am missing something).
However if you want to check if someone has moved the exe to new location while applciation was not running, you can place the location in registry/database/config file. Then at each start up i.e. Load event of very first form, you can check if the value is same and then take action.
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