At work, I sit with a window right behind my computer, and vape all night at my desk. Every couple months, it gets built up enough to notice, and a quick wipe with windex clears it up.
I had a guy fill in for me for two days, who was
vaping a dripper. In two days the windows were coated more than I create in weeks. I asked him how much he vaped while there, and he told me only 10ml (5/day), which is less than me, and the same vg/pg as me. In other words, I think it also has to do with the juice, some will film up quicker than others.