> How often do you off-road and need 4WD?

These are two separate questions.

I off-road an average of once a month, specifically to reach my usual shooting spot on BLM-maintained land. I don't necessarily need 4WD for that, but it's a good excuse to turn it on anyway.

I “need” 4WD when it snows, since 4WD/AWD + snow tires = not being required to chain up when chain controls are in effect, and because 4WD > AWD > FWD > RWD when it comes to snow driving (especially here in Reno/Tahoe, where the snow/ice happens on hills and having more drive wheels is a strict improvement over fewer).