When do Samsung Rant recent contacts drop from the list?

I don't think there's any way to remove a number from the 'recent contacts' list on a Samsung Rant. How long before a number is no longer considered recent and drops from the list?When do Samsung Rant recent contacts drop from the list?
The recent history list, if you select options and delete, or delete all it will remove that call, or the stored history of the calls and not the contact from your contacts list. I am not sure how/when the contacts aren't considered recent.When do Samsung Rant recent contacts drop from the list?
It takes quite a while for my recent contacts to leave the list. Doesn't matter though, I love the phone!