Simple and personal answer;each and every day!
I begin each day with a nice ISO clean-up with the glass components. If really dirty i will use Randy's Black Label (work like a charm!). I use the used ISO to clean the screen. I still have the same screen as the first day i got my vV.
I also clean the whip tube once a week. Put into boiling water for 20 min and then do a quick inner ISO soak while the tube's still hot.
Have fun with your vV!
Thanks ugobo!! This is a dumb question, but what is an ISO clean-up??