First off, i am not in the business, but i was woundering if you folks could help me out here. me and my wife are in dire need of a new lawn tractor. we were looking at a few of them, and one salesman mentioned horsepower per acreage. we have a large area to mow, almost 4 acres, and some on it is on a hill and i have to drive up and down. the one we have now is 13.5 horse power. theres another 13.5 horsepower tractor and a 21 horse power tractor for sale at sears where we were looking at them. after thinking about it, it makes sense to get the 21 horsepower tractor, and spend the extra case for something that would last longer. however, she is considerably more cynical and thinks its just a scam, and the salesman just trying to talk us into spending more money. what do you folks think?