Our scanning process with Nikon and Epson scanners does a superior job of capturing your images.  That said, old slides fade with time, colors shift to red and blue, and simply darken.  Prints fade and become less vibrant.  All images can be improved with post scanning corrections in Photoshop - even those shot by professionals.

Here are just a few examples of how "after scanning" Photoshop corrections can make a real difference - in some cases turning a bad photo into one that preserves that special moment.

The faces were in shadow. Our photo editing process corrects for lighting mistakes.
This old slide had faded over time.
Lighting, whether from fluorescent lights in an office, or a blue sky, can often result in photos with incorrect color. Snow is white - not blue!
This photo had quite a few problems - too dark on the left, too light on the right; the colors were dull.