Soon as you mention the word "passion", then you have the incentive and drive to make it work. That's the hardest step.
Also the words "burnt out" ring bells with me - as that's exactly what happened to me and I lost the desire to work 9-5 in IT, and my last two years was spend "wondering" what to do next. Not healthy - and I "lost" those years.
Finances are really important. If you are in a financial position to make the change, sacrifice a well paid and guaranteed salary - then it is an easier transition and it is not hard on the family.
I don't know anything about photography, but I know a couple of friends that spent years working for company that sent out photographers to function centers. The work was part time (and at night), but eventually one went pro after starting to do weddings. This is a guy that carried a camera EVERYWHERE with him. Again - goes back to the word "passion" !
