[Leica] I use UVa filters - when should is it critical to take them off

[goldframe1@yahoo.com]

Sorry - here goes - in know the FAQ's warned about asking such questions -
so I waited a month after coming on the list to do so.

I have always used UV'a and Skylight filters on my Nikon gear and now on my
M's lenses for the last 3 1/2 years.  Last year when I bought the 28mm f2.8
I immediately put a filter on, went up to Rocky Mountain National Park, in
Colorado, and exposed a roll.  Yes there were flares and the prints were a
little washed out.  So.......

For the user who just can't bear to let nasty contaminants get on the front
glass - when is it most critical to remove the filter for the best results??

Thanks - gold