Ok, so I'm going to be the unpopular vote here...my mom used toleave my brother and I in the car starting when I was about 8 and he was 6...but only when she had to run in quick to do something, like pay for gas before the credit card things were at all the pumps, or if she ran in to grab a pack of smokes, or something like that...just quick little things, never lasting more than 10 min. She always said that it was for time, because the whole time we would be at that place would be doubled or more getting my brother and I back in the car. I also think it depends on the child/children. How well behaived they are. My brother and I knew we'd be in some serious trouble if we didn't do exactly what my mom expected of us. I will admit myself, that I have left my son in the car, while I have run in the house to grab something I forgot, or to grab a drink from a soda machine. It takes me a good 10-15 min to get him in the car and strapped in, because he likes to do it on his own, with a little help from mommy. Now, I would never just leave him in there tho to go shopping or anything like that. Sometimes, especially when your crunched on time, or not wanting to deal with the hassle, and frustration, I can see it for quick things, as long as you can see your child, or know that they're ok.