Think hard about your tractor choice. Many of us here are hobby users. If a machine is out of commission for a couple of weeks it is a PITA but not catastrophic. If you are making a living with it, down time can bite you. A lot depends on how talented you are as well. Some guys can wrench, others cannot, and others do not want to. So decide if you need to have it serviced when it breaks and figure out who will work on it.
If you cannot find a reliable source for parts, that is a concern. Here is a link that may be helpful:
Parts
When I purchased my tractor, I decided the savings of an "off brand" where worth the risk. If I had to make a living with my tractor, I would have paid the premium for a Kubota. There are a lot of them out there, with very few problems. Plus they have an extensive dealer network. IMHO they are number 1 for a reason.
BTW, it is a good idea to talk to an accountant when starting a business. They can advise on equipment depreciation, tax credits, and tax issues.
Good luck with your new venture and I hope it works out for you.