Do unused AI credits roll over?

Within a billing period, unused AI credits carry over — they don't reset until your plan actually renews (weekly for Starter and Pro's weekly allotment, annually for Enterprise's terms). If you need more credits before your next renewal, you can also buy a one-time top-up pack — 200 AI credits for €5.99 — from Settings → Billing, which adds credits on top of your current balance without changing your plan.