It is a part time job. I keep a file folder on my desk where I put print outs of everything I am supposed to get miles for. Boarding passes, rental car receipts, hotel folios, online shopping shipment confirmations, etc.

I review it about every four weeks.

I have been accused of being cheap. I will walk out into the airport parking lot and find an abandoned luggage cart before I pay for one. (They are always free in Europe but cost about $2-3 at airports like Atlanta)