[adventured]

You can easily set a hard limit in your account to avoid that risk.

The pre-purchased credits approach burdens a lot more people than it helps, which is why it's an approach so extremely rarely used.

[sigmoid10]

I have set the hard limit, but because I never know how much time I'll have in a month for developing and testing these things it's pretty high and just a worst case fail safe. Pre-purchasing credits at a fixed amount for a variable time seems better to me than vice versa. And I would say most companies are already used to that from paying licensing fees and seats for other saas.