Great point re: age of tires.
For tires manufactured after the year 2000 the last four numbers of the DOT code indicate the week and year of manufacture. So if the last four numbers are 5208 that means the tire was made in the 52nd week of 2008.
If the DOT code is on the inner side wall just reach under the van with your digital camera and take a bunch of photos of the inner sidewall of the tires then read the code from the photos.
The tires on the 1997 van I bought were 14 years old! Way overdue for replacement. They didn't look bad on casual inspection. It cost me just under $1,000 to replace them.
