10 acres is enough to start...or end up with!
We started out with 4-1/2 ac the first year and added another 6 ac over the next couple of years. Most important lesson? Weed control. Next? Don't pick varieties to grow that there's not an established strong market to sell into. Often we pick some that are "interesting" to us, but forget that others need to be educated and sold on their benefits. Not a good idea.
If you're planting at a rate of 600-700 trees per acre, you'll end up with about 5,000 trees on that ten acres by the time you've subtracted out work space, etc. If you spread the harvest of those over 5-6 years, as you will need to in order to re-grow replacements, you'll be digging about 800-1,000 tree per year. At that level you will NEED your own spade, not relying on someone else's schedule to dig for you. In fact, even a couple hundred per year will demand your own equipment for the sake of economy and convenience.
Once you're at that point, I would suggest you go to treenurserytools.com for a good discussion of what you'll need.
Lastly, your cash outflow will not be substantial (as long as you do your own work) with seedling purchases and weed control (chemicals like Oust, Poast, and Pendulum), until you reach the point of needing the skid steer and tree spade.