One of the great uses of the small digital cameras is to be able to stick one under the rocker panels and take photos of both sides. This is a great way to see how much rust is forming (if any) and where it's forming. I just did this and I can see some new stuff I better get the oil on quick. It's also better to view the pictures indoors out of the weather. Doing this twice a year and saving the photos helps in seeing what damages weren't there before.