None of the above. I write in the upper right hand and lower right hand corners of printed Outlook calendars to track the beginning and ending segments for each month for 3 airlines. I keep the boarding passes to make sure I get credited. I try to reconcile the rental cars and hotels about every quarter. Even if I had a PDA, I doubt I would use it to track mileage...too much effort, besides if anyone saw me, it would prove I'm a mileage addict.