One has got to have a daytime job and stable income to bet. Going PRO is everyone's dream but the idea is not wise. It is just hard to earn/make the same kind of money as your daytime job, days ina nd days out.
Let's suppose you make $320000 a month. That is equal to $4000 without risk income per horse-racing day ( assumed 2 days per week for 4 weeks). OK , $4000 is not a big deal but that is a sure WIN $4000 , not a '$4000' net betting profit with a risk factor. If your risk factor is 50% ( ie pretty personal here), the $4000 would easily be blown up to $8000. So ,to quit the day time job, you have to win $8000 on each meeting. ALL meetings for 8 times. If you can do that, you can break even.
hence, I think a semi-PRO approach is the real PRO approach.