I'm curious as to how often you might (and I know it probably depends wildly) cut high frequencies as a matter of course.
For example, I usually cut quite a bit of low frequencies on most tracks just to keep the muddiness to a minimum in the overall mix. Do you also do the same on the higher end of the frequency spectrum?
I think most mixing engineers use a lot more low cut than high cut filters. The "modern" sound is loud and bright, so most people aren't cutting a lot of high frequencies out of tracks... more often they are adding even more high frequencies with EQ than cutting.
Personally, there are not too many times when I rich for a high-cut or low-pass filter when mixing. Low pass filters are certainly useful and used a lot when shaping synth sounds, especially resonant filters with that analog sound. But, it's rare that I'm rolling off the high end of any audio tracks during mixing.
The times when you may want to use a high-cut filter would be on distorted sounds that are too edgy and need some smoothing out, or any other overly bright or harsh sounds. Many times people smooth these sounds out by running them through very colored tube preamps or compressors that naturally smooth out the high end. But, low pass filters can be very useful in these situations also.
It could also be useful for creating some contrast in the song, by cutting some high-end on certain instruments in some parts of the song to subdue them a bit, and then bringing it back in on other parts of the song.
Or, could be useful if you simply have too many instruments with a lot of high frequency content and you need to tame the high end a bit and make room for everything.
Other times that I've used a low-pass or cut frequencies with a high shelf filter, is when I want to make a certain sound seem like it's further away from the listener. In the real world, high frequencies get absorbed and scattered more easily, so the further you are away from something, the less high frequencies you hear... so, you can remove some high frequencies and add some reverb to make sounds seem more distant.
Short answer, though, is that, in general, people don't usually roll off high frequencies from a lot of tracks during mixing, the way you would with low frequencies.