Why not buy a 256 GB card and use it for a while, see if it does make a difference for you? Maybe your question might get more responses on the Digital Video subforum?
I don't shoot video, am strictly a stills photographer, so no real sense of how much capacity is needed on memory cards for that kind of photography. I DO, however, shoot stills and there are times when a large-capacity card is absolutely needed. When I was preparing to buy my Sony A1 camera, I wanted to go with the faster CFExpress cards so purchased a couple of 80 GB ones. For most of the kind of shooting I do, especially macro/closeups/tabletops, that has been quite sufficient. However, then for a while I was shooting more bird action and had the camera settings for 20fps at Continuous High+ -- and, yeah, that kind of "burst mode" eats through card capacity in nothing flat, so I did buy myself a 160 GB CFExress card as well, and that helps significantly when shooting in that kind of situation.
A lot depends upon the situation which one will be shooting in, the subject of the shooting session and the amount of time spent. A few minutes standing out on my deck firing away at the geese and the hooded mergansers can be fine with an 80GB card or two when they're just leisurely floating around. I have two 80 GB cards in the camera at all times. When seriously interesting action occurs and I am suddenly shooting at a more intense level, that's when I appreciate having at least one card with extra capacity so that I am not interrupted in the midst of something exciting and can no longer shoot because the cards are both exhausted.
If I were to be going down to Florida and spending a week or so shooting the beautiful birds down there I would be buying seriously large-capacity cards before ever leaving home, and they would be the ones in the camera during the various excursions to wildlife sanctuaries, the wetlands, the other places where the birds spend their time.
Of course there are a couple of issues which go along with using large-capacity cards. One is the old adage of "don't put all your eggs in one basket," and so some photographers do hesitate before using cards which store so much -- because those same cards can also be lost, corrupted, or have something else happen to them which means that the images on there -- the thousands of images -- are gone, unavailable, lost.....
Another issue is that it takes quite a while to look through, evaluate, and cull the best images when one is dealing with a whole bunch from a large-capacity memory card!
With video, of course things are very different. I have the feeling, though, that probably it is better to have a card with more memory capacity than one thinks one will need than to have one which does not have enough.
