If one puts the words "always," "UV" and "filter" into a Google search, one can see that, to many, many people, it's common good practise to permanently affix a UV filter to the lens for protection.
I think i's a shame that this is propagated so widely, because it should be a judgement call, every time.
I don't even own a UV filter, excepting the integral one in front of the sensor. I just cap up regularly.