I carry a full range of filters with me to solve many problems in the field. In my b&w landscapes I prefer a lot of drama in my cloud filled skies. In the Southwest, where I primarily photograph, too strong a filter will completely wash out warm-toned complimentary colors in foreground. So I have settled on a No.16 yellow/orange filter as my "go to" filter in the field. It gives me sufficient drama in the skies without overly lightening foreground objects like yellow sandstone and arid grasses. This is equally true when photographing historic architecture and ruins in the Southwest where buildings are often times constructed out of warm toned adobe, sandstone or covered in stucco. My 1991 monograph "Chaco Body" with poet V.B. Price, about the Anasazi ruins in Chaco Canyon, New Mexico, illustrates my filter preference well. Almost every image that includes sky was shot with the No.16 filter as well as some of the details of petroglyphs where the light yellow petroglyph was etched through the darker desert varnish.
I prefer Lee polyester filters for their clarity, light weight and compactness, but my no. 16 filter is so important to me that I back it up with a B&W glass version so I am never without one.