You want to delete recent history because you're covering your tracks (porn, "how to get a divorce", etc). Those history clearing options predate private-mode b

You want to delete recent history because you're covering your tracks (porn, "how to get a divorce", etc). Those history clearing options predate private-mode browsing. They don't have expiry because the browser makers figure if it gets slow, it's a bug, and I'd bet most browser developers wind up trashing their profiles all the time anyway.