To maintain an active data feed, you must update the feed every:
- A) 30 days
- B) 6 months
- C) 1 year
- D) 24 hours
Explanation: Up-to-date product feeds with keyword-rich descriptions will entice users and keep your ads showing at the right moments, while inaccurate feeds can lead to product or account disapprovals. The best way to ensure this is to update your feed whenever you update your site. As a result, product feeds should be updated at least every 30 days.
Read more here: https://support.google.com/adwords/answer/6167192?hl=en