How to set the parsing logic correctly?

Question

PHP

Guys, welcome. In general, the question arose of how to properly remove ads from the database that no longer exist on a third-party resource.
I have a base - in which declarations are written when parsing. But if, for example, a couple of ads have already been deleted on a third-party site, how would it be optimal and with less resources to check this fact and remove them from your database?
There are options in my head, but they seem a little "cumbersome" to me.
Thanks in advance for the answer, as it is done among the people. =)

Answer 1

Save URL where parsed from and date. Check every day for cron records that are more than N days old.