[Leica] To Filter or Not?

["Bryan Willman" <bryanwi@seanet.com>]

I am thinking about a very old practice of mine
(starting in the 1970s)

Putting a skylight filter on the front of all lenses.

Theory A:
It protects the lens.  You can pitch the
filter and get a new one every so often
for much less than the price of the lens.
Cleaning the lens will scratch it, or at
least rub away the coatings.

Theory B:
It's another layer of glass to be dirty,
cause flare, etc.  With modern very soft
cleaning cloths (like the little white ones
Leica sells) and modern relatively hard
coatings, careful cleaning will not scratch
the lens.  The amount of protection the
filter gave against rain, etc. wasn't worth
all that much anyway.

And so, leaving flames aside, what do
people think?  Can you clean a modern
lens without scratching it or rubbing away
the coatings?

bmw