I just tell myself each tool has it's use and in the case of plows, discs, and tillers, each is made to do things a little differently and save wear on the other.
-If you run a plow to turn the soil over, that does a better initial breakup of things than a single pass of a disc.
-If you plow before a pass with the disc it is easier on the disc because the soil has already been cut near the depth the discs ride and they can fully do the most work in a single pass as possible but not be impacting a lot of solid ground (one pass of a plow will soften things as much as two or three passes with the disc allowing the disc to give a better result with less work).
-Also plowing before discing puts the sod and other top-layer organic material deeper.
-One pass with a plow and one pass with a disc has most things in the condition of 4 or 5 passes with the disc alone.
-If you want to finish off by tilling it into really fine garden type soil, generally a single, slow pass with a tiller brings you to a "bagged" type texture and the wear and tear on the tiller and tractor driveline is very minimal.
3 passes with a different tool each time, each making the other's job easier. Saves tools and saves fuel.
The main failing of this (as is typically pointed out), is it does require greater amount of manual labor as it requires changing the implements. If I was afraid of a little bit of manual labor I'd sell out and move to the chity... I just call each insurance for the other to justify the cost. Plow protects the disc, disc protects the tiller, it all saves me from using a hand shovel, so I hook each up as needed. I just got my own disc (after borrowing implements to get my garden ready to till with a new tiller I recently acquired) and I can't wait to use it.
Have I talked you into a plow yet? :stirthepot: