If you're not being facetious, depth in this context refers to the overall quality of your staff.
A good example of a lack of depth would be the Indianapolis Colts, who with the loss of Peyton Manning had a dismal, almost winless season.
A good example of a team with a lot of depth would be Ask Ketchum's pokemon. He's got a Charizard, a Butterfree, a Wortortle, a Pidgiotto, and Pikachu. If one of his pokemon gets injured, he has a handful of equally good pokemon suited to other tasks that can fill in.
A good example of a lack of depth would be the Indianapolis Colts, who with the loss of Peyton Manning had a dismal, almost winless season.
A good example of a team with a lot of depth would be Ask Ketchum's pokemon. He's got a Charizard, a Butterfree, a Wortortle, a Pidgiotto, and Pikachu. If one of his pokemon gets injured, he has a handful of equally good pokemon suited to other tasks that can fill in.