I was pulling up my service records....I stopped keeping tabs awhile back. Looks like on paper, I last changed it 50,000 miles ago - which sounds about right from a PM standpoint to do it again. Somehow I think when I did some service 35000 miles ago, I might have changed touched it. This I don't have a record of, but I feel like I touched it.....it's my own fault for slipping on my notes.