Extend caching for less or more than the default 1 week setting
ImportFromWeb caches the webpages it fetches for 1 week. So whenever Google Sheets refreshes the =IMPORTFROMWEB() functions, the content is retrieved from the cache and no credits are counted.
You can extend or reduce the default cache duration (from 1 hour and up to 4 weeks), so you always keep control over the freshness of your data and your ImportFromWeb usage.