What happens if you use the next.revalidate option in the fetch function and conditionally set its value depending on some criteria?

For example, if I know externally that I need to expire the cache, and I pass 0 in as the value for one call, but then a subsequent call uses '30', does it use the cached value from the call where it was '0'? The docs kind of imply that the value is supposed to be static for a given request and Next determines page-level caching parameters based on it...