Hello!
Your question is really for DPUG.
You should use a UV or Skylight filter in every lens you have in order to protect it and to avoid cleaning the front element so often.
Other filters for B&W and Colour use as dictated by situation.
This really isn't for DPUG, because he's asking whether or not to use filters for film shooting.
Also, using a lens solely for the purpose of 'protection' and 'cleaning' is not ever what a filter was designed and developed for, and using a filter for that purpose is strictly succumbing to marketing hype by the filter manufacturers. A front element of any lens, even the cheapest lens made, is worlds thicker and stronger then a 'protection' filter. And when you talk about post war lenses, even the coating is stronger then most filters. There isn't a filter made, at any price, that doesn't affect the image quality, and while some filters may only affect it in a very minimal way, it's still affected.
As for cleaning, do you not have to clean the filter? And seeing how filters aren't coated like a lens is coated, you have a greater chance of damaging the filter with normal cleaning then you ever would with normal cleaning of a front element.
Sorry, but those two reasons alone are not the reason to use filters.
***WARNING WARNING WARNING*** - Brief digital reference;
Digital cameras (sensors) have a UV 'block' built-in, making the need for a UV/Haze filter completely unnecessary. All of a sudden, filter manufacturers saw a decline in UV filter sales when DSLR's came about. Almost every lens sold for folm photography was sold with a UV/Haze filter, and that market vanished with the advent of digital. So the filter marketers came up with the use of 'lens protection' at the sacrifice of image quality. You will never find a UV/Haze/protection filter on any of my personal digital equipment.
***Back to Analog***
Film does not have anything built into it to not record UV, and different films will behave differently, depending on their sensitivity to UV. This is why the UV/Haze filter came about. The filter cuts the atmospheric haze down a bit, and makes for better images. Just look at any of the comparison photos when you do a search for 'UV filter' on google. UV filters are pretty much needed for analog capture.
So in answer to the OP's question, yes, folks are still using filters in the analog world. It's needed in the analog world.
One more thing about filters for protection. About 3 years ago I made a video (looked for it on youtube, but I may have deleted it) where I dropped 1/2" carbide tipped drill bits onto a couple of lenses, with and without a filters. When dropped from about 2 feet, the filter smashed into nice shards, and in 1 case a glass shard then scratched the front element. Without a filter, the front elements sustained no noticeable damage until about 4 feet, and that was only chips. It took to about 6+ feet until I was able to crack a front element. Read into that what you would like.