Nighttime: 

When visibility is low or the surrounding environment is dark, reflective clothing helps others notice you.

Dawn or Dusk: 

These periods are particularly dangerous due to reduced visibility, even if streetlights are on.

Poor Weather Conditions: 

Fog, rain, or snow can make it harder for others to see you, so wearing reflective gear becomes more important.

Work Zones or Construction Areas: 

Workers and contractors often wear reflective vests to stay visible to moving machinery and passing vehicles.