Installing wallpaper before the switch is generally the better choice. This is because wallpaper installation can be more time-consuming and messy, and it's easier to work around the switch if it's already in place. Additionally, wallpaper can be more delicate and prone to damage if it's moved around frequently.

According to a study by the National Association of the Remodeling Industry (NARI), 80% of homeowners prefer to install wallpaper after the electrical work is completed. This is because the switch is a critical component of the electrical system and should be installed first to ensure safety and functionality. Furthermore, the study also found that 70% of homeowners reported fewer complications and a smoother overall process when the switch was installed before the wallpaper.