I am on the edge of a major city - I ride for just about all errands including work errands and meetings. My exceptions are Friday/Saturday nights (potential for crazy drivers) and things like Costco (which is only a twice/year trip anyway).

When I moved here ten years ago, I had no money and no car and it was a 20-25 minute walk to the nearest subway stop (there were buses for rainy days but they weren't as frequent). So I evolved into figuring out things for the bike. Even silly things, like only carrying a grocery store basket (instead of a shopping cart) because once the basket was too heavy, I wouldn't be able to fit things on the bike! I also have bar ends on my commuting bike - very useful for tying bags of produce from the farmers market, or hanging 1/2 gallon jugs of milk.

Oh - and I try not to do too many errands at once. I can lock up my bike only so many times before getting "errand fatigue" and getting cranky. I'm sure it would be even worse in a car, but I wouldn't know! Thankfully that's a novelty