When you say you have "a fair number" it would depend on just how many this is which way to go. It wouldn't take a large number of slides to make it worth getting your own scanner, assuming that you don't already have a flatbed scanner that is slide capable.

The advantage of having a digital image is that some imperfections on slides can be adjusted. For example, dull colours brightened or contrast adjusted, and dust specks or scratches repaired.