Are roller blinds better installed inside (recess) or outside (face fit) of window?

Roller blinds are commonly installed inside window recesses in Australia, offering a clean, minimalist appearance whilst providing privacy and light control. However, for bedrooms requiring total darkness or windows lacking recesses, the best approach is to install the blinds outside the frame, covering the entire window opening. This technique, referred to as Face Fitting, effectively minimizes light intrusion and is regarded as the optimal choice.