<font color=blue>When I plow, I can tell where I am by looking at the plowed area behind the plow blade, and then can see if I am on the gravel drive or off in the grass. In 34 years, has never been a problem knowing where I am plowing. Now a blower might be different, but even there, seems one can still see where the snow is blown away</font color=blue>
Beenthere - you're right about not needing markers if you have piles along the side of the road. With a blower, you generally don't end up with piles along the side that you can use as a future guide. The little "edging" that you do end up with is quickly smoothed out in any wind due to drifting.
I find it's actually harder to stay straight on the driveway when using the tractor versus driving the car up it due to the fact that you're going so slow (tractor vs car).
It's easy for me, at least, to unwittingly start veering off course. Most of my snow removal is at night, and, when you combine the dark with the blowing snow, I am constantly watching my wheels to make sure that I don't go off the edge.
My driveway doesn't have flat areas on either side of it. The front snowblower I have only raises up about five inches. If I were to slide off the driveway, I would easily get hung up and would have to pull the tractor out with a car. That happened to me about the second time I cleared the driveway; neighbor had to yank me out with his wheel loader.
If I plowed the driveway with a truck, I'd have alot less markers.