Most of the time, 2-3 seconds is plenty. However, I have had occasions where I needed longer bursts. With my D850 (a somewhat limited buffer as well) I usually was able to mange with careful controlled bursts. My understanding is that it does clear fast. So, if there's a chance to let off for a moment during the burst, you can get a lot of buffer back (same with Nikon).I will say the buffer kind of sucks at 14 bit. You get 4.5 seconds until the buffer is full and I’m guessing a few seconds to clear it. View attachment 13728
Another thought is this - I use my a9ii at 10FPS quite a bit. For "lighter" action that's plenty of FPS (like an egret lazily flying by). However, for more active subjects there certainly is a benefit to going to 20FPS - even at that high frame rate, every shot will be different.