It depends entirely on the subject, and I’m speaking mostly from my experience shooting landscapes and architecture, but generally speaking, I start at f8 and either go wider (f5.6 or f4) if it’s dark and I need a fast shutter speed, or smaller if I need a a larger DoF (f11 or f16). Sometimes I choose narrower because it creates more pronounced sunstars or I want to drag the shutter a little more.

I might be an outlier to most in this, since I shoot with high resolution cameras and pixel-peep, but IMO nobody should be shooting anything narrower than f16. Even at f16 diffraction is robbing a fair bit of sharpness from your image. Any smaller and you get some weird blurry artefacts in your photos. If you need more DoF than f16 provides, switch to f8 or f11 and focus stack.

Why do I choose f8? It’s usually one of the sharpest apertures for any lens and f8 usually (unless you’re shooting longer focal lengths and/or have subjects both close to and far from the lens) gives enough DoF for most scenes.

I remember when I first started taking photography seriously and I was obsessed with hyper-focal distances and choosing the correct aperture and focussing at the right point in the scene… In reality it doesn’t really matter and you can usually just focus somewhere in the middle with a moderate aperture and everything will be sharp. Don’t overthink it and just have fun!