Riding mowers are best suited for yards measuring one acre or larger. A model with a 42-inch cutting deck is great for mowing up to two acres, so if you have more land than that, you'll want to spring for a 46, 54, 60, or 72-inch cutting deck. If you're right on the threshold, you can get what's known as a "mini rider." They usually have compact bodies for easier storage and 30-inch cutting decks to make short work of lawns that are just a touch too large for a push mower.