The amount of video that must be re-done by smart re-prepare is not a function of how seemingly minor your change might be. Once you change the video or subtitle or audio in any way whatsoever, then the VOBs for that portion of the project must be re-built. If you have only one titleset (basically meaning that you have just one main video stream), then the entire thing will be re-built.

Smart reprepare is a fabulous feature, but the place where it is really useful is when you make changes in the menus, like moving text or changing navigation, or putting in a new background picture. In that case, the reprepare is almost instantaneous. We just did a series of five DVDs with customized main menus for each. It took approximately five seconds to create each custom disk.

Given that, Sony here's an idea for your next release: How about "mailmerge for DVDs?" By that I mean, how about letting me specify a list of pictures for the background of any given menu, and then letting DVDA burn each disk with the next picture in the list? This could also be used for watermarking or IDing each disk -- a very effective way to trace the source of a pirated disk: Since each disk would be unique, you would know which customer let the cat out of the bag.