Cost limiting was how v0 stats are rate limited, you are given a specific amount of ‘cost’ to retrieve stats for a period of 15 minutes and after you use it, you must wait 15 minutes for the next window to open up. You should inspect the headers to see cost remaining go down after each stats query you do (the more data you request at once, the more cost you will use), and generally follow our best practices: https://dev.twitter.com/ads/analytics/best-practices
Your application may not be able to sync all of the stats for an account within a single rate limit window, and may need to run for up to several hours when syncing a lot of data (while waiting for the next windows to open up). A lot of this is simplified with the async job syncing of v1.
