Depends on the day - I live close enough to work to walk, and I've done that in the past for torrential rain. There have been days when I've put off errands for rain, and once or twice a year I'll take the shared car (we have just the one) for a longer errand in weird weather. For most errands it is easy enough to knock them out on days with less rain.

I am, however, weak, and let the wife get groceries in the car rather than collect them myself. It isn't really safe to bike to either nearby grocery store, though (and probably less safe with panniers full of food).

On on the other hand, many of the recent local pleasure rides have been in the 30s and rainy, so...