I only have the kit lense and the 55-200 cheapos since entering the Pentax realm compared to most of you guys, seeing this thread before i got my kit i decided to go sans filter but all my prior/current systems have filters (UV) as protection. I've only had one mishap where the filter (B&W) was the only thing damaged/broken when i dropped my bag with two full Mamiya 6 systems off a ledge everything else was fine but that one filter

I will put filters on the more expensive lenses i acquire in the future though.