I use a glance to see if I have the correct change. I have gotten Susan B. dollars by mistake and didn't realize it but usually, the years I spent working a lunch counter has done me good over the years. I very rarely use a drive up window. It's just a way to churn higher profits catering to people too lazy to get out of their cars. Yes, if you have three small children, it's handy. I stop at a doughnut shop on the way to work some mornings. I usually walk out with my order while the same cars are sitting line. This is with most of the help at the drive through window. The last time I used a drive through I was on a cane and just wanted an ice cream cone. Second car in line. Wait, and wait, and wait, then wait some more. 4 teenaged girls getting a huge order and by the time I pulled up, the line stretched around the building.