when do you use "hours upon hours"

[soleiljy]

when do you use the phrase "hours upon hours"?

i can't find the exact meaning of the phrase, and got stuck when reading the following phase.

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Lee could have simply walked off the stage and started what will surely be hours upon hours of media interviews and photo ops, but instead he took an off-camera moment to thank those responsible for his ascent to stardom — a classy move.
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thanks in advance!

 

[billmcd]

Use it to describe something that takes an excessive or unusually great amount of time.