Your right, your land, your time & machine, who cares how fast it gets done... to a point.
Example- A guy in town decided he wanted an addition to his house. This required digging down and extending his basement by 12' x 24' x 5'. Guy rents a mini excavator from the local hardware for $600.00 plus tax a week. Its a wee little bobcat with a bunch of hours. It takes him about 2 days to dig this all out and make a big pile in his yard, which he intends to rent a skid loader and move around. I'd have came over, dug the hole & spread or hauled the material away for the same $$, and would have been a short day for me. Sometimes it pays to bring in the right equipment, even when you have your own.
Oh, and for ripping small trees out, try an excavator w/ thumb, even a small 8-10 ton, on those little 10" stuff you will be suprised at how fast it goes.