Image optimization returning 402 on Hobby after 1,000 source images

Images started returning 402 Payment Required from the optimization endpoint today. I have about 1,100 unique product images. Is the 1,000 limit per month or lifetime?

Per billing cycle. It resets on the first of the month. In the meantime you can serve the originals by setting unoptimized on those images, or move the catalog to a CDN loader.