Title text:
"How does the spring not run out almost immediately?" "We pull it back REALLY far."
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3244/
You're probably right, at the same time, a spring that isn't overloaded can usually take an absurd amount of cycles: Just think about how long the suspension on a car typically lasts compared to a lot of other parts.