Question

The flow of my program is the following.

On form load, the program will check current date. If it is in a new month, some function is called.

Any ideas how to do it?

Answer 1

Assuming you save the date of the previous run of your software, you could have code smilar to this:

'Get the date of the previous run, that you could have saved in the database    
Dim previousDate = GetDateOfPreviousRun()

Dim currentDate = DateTime.Today()

If currentDate.Month > previousDate.Month OrElse currentDate.Year > previousDate.Year Then
    SomeFunctionIsCalled()
End If