How do metaphors and extended metaphors differ?

Metaphors will often only involve one or two comparisons, while extended metaphors can cover pages or even entire stories.

Metaphors are simple comparisons. They only compare a few things at a time:

"She was their light, their sun, their sky."

Here, the woman is being compared to three things. But it is only a simple metaphor because it doesn't go on for too long.

Extended metaphors compare the same thing repetitively over a few lines, pages, or even whole stories. Example:

“Bobby Holloway says my imagination is a three-hundred-ring circus. Currently I was in ring two hundred and ninety-nine, with elephants dancing and clowns cart wheeling and tigers leaping through rings of fire. The time had come to step back, leave the main tent, go buy some popcorn and a Coke, bliss out, cool down.” (Dean Koontz, Seize the Night. Bantam, 1999)

Here, Koontz is comparing his imagination to a circus. However, he uses multiple sentences to do so.

...Am I making sense? You might want to go here for more help:

http://literarydevices.net/extended-metaphor/