Do Spark Credits expire?

It depends where they came from:

• Sparks from your plan last for that month. Anything you don't use doesn't roll over — you get a fresh batch when your plan renews.
• Sparks you buy in a Spark Credits pack last for one year from the day you buy them.

When you spend, we always use the Sparks that expire soonest first, so you never lose some while others sit unused. We'll also email you 30 days and 7 days before any bought Sparks expire.