I’m glare-phobic. It’s amazing how much glare there is to be cut out. When shooting water it’s such a satisfying thing to turn the CPL and be able to see right through the water.
Sometimes CPLs are a detriment, so I’ll either turn them till the effect goes away, or just remove the filter. When I shoot handheld at night, and need all the light I can get, the CPL comes off. During the day, though, always on.
BTW, I’m using B+W xs-pro kaesemann high-transmission CPLs to minimize loss of light for general purpose shooting.
I’m so OCD about them that I outfit every lens with its own B+W CPL to eliminate the hassle of putting on/off. Fortunately 52mm filters for the Loxias are not too expensive (except Breakthrough, which is absurdly expensive).
Breakthrough NDs have a superb reputation for color accuracy, so that’s why I got their NDs. Ridiculously expensive. Breakthrough have a 300 day return policy (if purchased directly from them), so they better be amaze-balls-great or I’m returning them for that cost.
I use a Lee square CPL when I use my filters for landscapes but generally don’t use screw on ones beyond that. I purchased a 82mm B+W kaeseman one when I ordered the 16-35GM but sent the lens back as it was defective and ended up with an unused filter