Yes 10 acres is quite a bit and if I had a big mower and a tractor I'd mow even more.
No, I think I would never give up the mowing job, I enjoy it too much. I'm sure it would be less expensive to hire it done because a nice tractor costs a fortune but I plan to be in a position that I don't care that much about the cost. lol. I'll just have to convince Mrs. J!