If I'm saving it for later, I don't want you to delete it ever. People are busy and they might not get back to it by a gamified experience limit. Would just use a service that doesn't delete it, like my bookmarks
it’s not his needs, it’s something that why people use read it later services.
your product is not solving a problem that read it later services has, actually cannot finding saved items is a problem for a read it later service.
better call your service something like temporary bookmarks