I recently returned from a 6 week tefillin and mezuzah checking campaign. In dealing with mostly balabatim, many seniors with minimal yeshiva education, the number of batim and retzuos that lack paint is staggering. (The number of people wearing their shel rosh too low is also a very serious issue and not easy to tackle when they've been doing it for years without anyone telling them otherwise. I'm glad I've been able to made a dent over the course of a number of visits.) I'm attaching a picture of a shel rosh that blew me away. The side of the retzuah that you see is the front!! Fortunately he now has properly painted batim and all black retzuos.