This is only an example...suppose a module wants to make sure an application object, called oApp exists:

if vartype(oApp) <> "O"
    * Houston, we have a problem....
endif

>>>>>Yes, you should avoid using VARTYPE() if variable/property may not exists.
>>>>
>>>>Vartype() can return 'U'. So when is it proper to use Vartype() and have it return 'U'?
>>>
>>>Never.
>>
>>Really? Never use vartype() to check for the existance of an object?
>
>I'm not sure what you mean.