I’ve done well over an hour before (one way), but it definitely takes planning so not anywhere close to casual. At that point, perhaps other transportation may be used to return. And/or even if a daily/weekly occurrence, it takes discipline to do things like leave on time and stay informed throughout the day to handle weather events, plus wearing certain clothing to handle sweat and sun and rain etc. Biking is definitely preferable to walking for that level of distance/time, though I’ve done both.
More routinely, and perhaps with little notice, maybe… 20 minutes? (one way) It’s hard to say bc it depends on what stores are where, whether the purchases will fit comfortably into my bag, etc. But I’d leave at a moment’s notice for such a trip if need be and the conditions are conducive to it.
What about you: what’s your cutoff?
I don’t know how representative my preferences are for the rest of the USA, but I live in a dense city.
I have a bicycle (and my city has plenty of bikeshare rentals scattered all throughout) so I’m usually not willing to walk more than 10 minutes.
When the weather is nice, I will walk within 5 minutes (roughly 0.25 miles or 0.5 km), bike within 30 minutes (roughly 5 miles/8km, depending on lights and traffic), and drive or Uber/Lyft beyond that.
When the weather is bad, I usually take mass transit if I can do it with less than 2 transfers, or I’ll drive/Uber/Lyft otherwise.
My choice between driving and Uber/Lyft is usually driven by some combination of cost (including parking), convenience, and whether I intend to drink.
Having access to bikes everywhere surely must make a wonderful difference!:-)