I admit, the first couple of years in my photography business, I would report an extremely rough estimate of how many miles I’ve accumulated for tax reporting. An estimate basically means zero to the tax man, so I hope he isn’t reading my blog. I absolutely hate logging anything manually on paper, so I searched for many iPhone apps that allowed me to track my mileage, which worked for about a month because I would always forget to run the app after my trip, not to mention I still have to plug in the data.
I finally discovered a simple device that does pretty much all the work for you. I’ve been using the GiSTEQ GPS TripBook for 4 months now, and thought it was good enough to highly recommend it. The TripBook is a dongle that you plug into your car through a USB car charger. I recommend getting any sort of dual USB charger so you can charge another USB device while using the TripBook.