Currently been doing this since October. My all in cost (rental rate, fees, taxes) is actually lower than my last car payment that I had. I rent one month at a time, and it usually is 10 minutes or less to drop off the old car and leave with the new one. Each rental is 4-weeks (28 days), which is under the 30 day limit for my credit card for insurance.
Friends thought I was out of my mind, until I showed them the math. ^