I would not leave them home alone if I was driving anywhere (what if you had a car accident or car trouble and your trip wound up taking a lot longer than planned?). I would leave them briefly if I was going to be really close by (like walking over to a neighbor’s house for a few mins, or walking my other kid down to school 2 blocks away or something)

Yes, my oldest when nearly 7 was left at home alone for even longer than 30 minutes. Sometimes a couple of hours. And this was before devices to keep kids entertained (although we had TV).

My almost 8 year old has asked to be left home before, but we never had a chance to try it out. Because of this thread I asked her yesterday what she would do if someone came to the door, if there was a fire, etc. She answered everything mostly correctly, but then later she brought it back up and said she did not want to be left alone for "another few years." I think the questions made her think about it more tangibly and she got nervous. So if OP is still reading, maybe take that as a cautionary tale. She may like the idea as a hypothetical, but could get freaked out when confronted with the reality.

I plan to start at 8 for very short time periods (10-30 minutes). I have left him alone to go for a walk or to a neighbor's house, which I think is good practice.