Jamie, you sound like me... Last winter, I sent in a couple rolls... One that I had just finished, and one that I thought was the previous roll I shot. Got'em back, and realized that the one I thought was the previous roll, was not. It was one from 1996/97... Needless to say, the photos on the CD needed to be run through Photoshop for correction of color and adjustment of the saturation... My problem is that I go through rolls pretty quickly, but let'em stack up for a while before I send'em off to be processed... I once had about 15 or so rolls that hadn't been developed. Including one that was an old Kodacolor VR roll that didn't have the DX film speed coding on it.
-J