topcat wrote:
Use it only when you are going to be using it. Why would you keep it on?
A polarizer works at 90ยบ to the sun, for maximum effect. Also, it can reduce some reflections.
If it is not helping you, why would you use it?
Only for the sky...
So much debate and conflicting information touted as "fact" by those who do not understand the basics.
Any reflective surface, especially glass, paint or water can be manipulated to a positive effect and you can reduce reflections... saturate color... and improve contrast no mater what the angle is. In fact you can adjust for multiple angles and stack those images in your post process editing.
I have been a published professional automotive photographer for ten years now and have a polarize filter is in front of my lenses at least 99 percent of the time, indoor and out...