* They're servicing an incoming HTTP request.

* You're interacting with a console.

They're hair-trigger inactive otherwise. They don't bill CPU unless they're active. The idea is that there isn't really any uncertainty about when it's running; when you stop interacting with it it stops metering.

This is a new shape for a cloud computing thingy and there'll be snags this week with it, but we don't make our money by billing people for stuff they don't want. We've always gone out of our way not to nickel-and-dime casual users and we're trying hard to find new ways to lean into that here.

(Destroying a Sprite you're done with is a perfectly reasonable move; they're disposable.)