Hire mowing is tempting, but it is hard to make any money at it. Well, let me put it another way: it is easy to lose money at it. There are a lot of yahoos out there hiring out bush-hogging for way too little, not having insurance, not covering their transportation, or depreciation on their tractor. By the time they go out of business three months later, somebody else has taken their place. In the mean time, anybody who wants to actually run a sustainable business is being priced out of the market. It's not to say that it can't be done, but you need to get customers who are willing to pay a fair wage for someone who is going to act like a professional. Or you need to understand that you're working for beer money and little more. But bush-hogging is very hard on a tractor. I bush-hogged just a little bit, and I did more damage to my tractor in that time than anything I've ever done around my own property. The problem is that you are often driving blind, and you're going to run over something or get hung up in a rut or who knows what. You'll snag a hydraulic line or bust up your bush-hog and then where are you at? Fixing it out of pocket, and all the tiny amount of profit you made on the last three jobs goes to fixing up the tractor. Oh, and let's not forget that as soon as you do work for hire, whatever insurance policy you have covering your tractor (if you have one) goes out the window. And, worst-case scenario, you damage somebody's property and they sue you, and the fact that you don't have business liability insurance (because who can afford that on a bush-hogger's pay) means you're personally on the hook.
I say all this as the voice of experience. When I first got my tractor, I had the idea that I would help cover the payments hiring out bush-hogging. I did a few jobs before deciding that it just wasn't worth it. That may not be everybody's decision, but it was mine.