How Much of a Gap Between Focal Lengths Is Too Much?

When you’re assembling a set of lenses, it can be tempting to try to cover all the important focal lengths without any gaps between them. A kit of 14-24mm, 24-70mm, and 70-200mm lenses is a popular one. So are sets with overlap, like a 16-35mm, 24-105mm, and 70-200mm.