It also comes down to what lense you’re using. Personally, I never bother changing my shutter speeds. That’s because I have found on the 75-300mm lense, the best aperture range is f8-11 (I use this on Av mode). F11 produces the best results, and I’ll try to shoot that high if the weather allows me. During bad weather, I will only go down as far as f8. If I try any lower, then I know it’ll be a waste of my time as the results will certainly lack in quality and sharpness. All of this is at ISO100-200 to.

I don’t know the best aperture ranges for any other lenses, but if you tell us what lense you’re using then some others on here may be able to give you a clue.

The only time I’ve ever changed shutter speeds, is when I’ve had to go fully manual on things such a night shots.