Some remove to reduce image from degrading. Every filter you stack will degrade the image. If you need to stack then use pro filters which cost 2 to 3 times more.
A lot depends on yourself, if you are happy with the picture from stacked filters go ahead and stack!
Do UV or skylight filter degrade image? or is super hmc the only solution? cuz I"ve read books where the author swears by not using anything other then polarisers, says even the focusing accuracy maybe be affected by UV or skylights.
As I said earlier on, any filter will degrade a photograph. To what extend it depends on the make of the filter and the filter maker. If base on you experience you can't tell then you can happily carry on taking pictures with a protective filter (usually UV or skylight).
Filter affecting focusing? Well I never got affected, maybe this is in reference to special effect filters.
Im surprised that the poll results indicate a split opinion.
This is suggestive of poor professionalism and utter disregard for photo quality :thumbsd:
At the end of the day, its the photographer that makes the pictures