Hello,

I suggest to log some info and to increase or to decrease the amount
of information as far as you need:
http://log4vba.everage.ca/

Advantage: With the right level of detail you will even know (even
long after somebody has run your app) what your users did when.
Disadvantage: Might slow down your app (but - hey, you can switch it
off/on whenever you feel the need).

Regards,
Bernd