Originally posted by braver I'm always using B+W glass protectors on my lenses
I never use protection filters but I can understand the logic. And on older film era lenses they made a lot of sense, a good UV filter helped cut UV light and also protected the front element of lenses whose coatings were not all that tough and often got scratched. Modern coatings however are incredibly tough and largely eliminate the need for 'protection' filters.
However, the 15-30 leaves you no choice as it has no filter threads anyway. My personal philosophy is: lens cap always on unless in use, and if the lens cap is off the hood is on. Whether you use filters on your other lenses or not I guess that's the only choice on the 15-30.