FWIW, I've had a M1, M1 Pro, and M2 Max laptop (different work/personal machines) all with fans, but I've
never heard them turn on in several years of development work, no matter how many windows, apps, etc. I had open or how many things I was compiling.
The only times I heard the fan turn on were when the GPU was heavily burdened, like AAA games, especially when they're emulated in Rosetta or Wine. But for everything else, the fans never came on. These days, I suspect they'd come on for AI training (but I never tried).
Just anecdotal data for anyone contemplating an upgrade to one of the fanned versions. They tend to be more powerful than the non-fanned versions, but in regular everyday use you would likely never hear them. I didn't even know they had fans until I tried to play graphics-intensive games on them.