Once a week, I mow 1.5 acres.
Now run a Hustler Raptor 22 HP 54" zero turn, before that a 17 HP 48" Deere riding mower. The Deere lasted 16 years. Always thought it was a bit too small, but it was the model the salesman recommended. Neighbors were surprsed the Deere lasted that long, but I changed the oil every 20 hours with a high temperature oil instead of the Deere recommended 25 hours. Also periodically cleaned out/off the air filter plus a yearly tune-up.
Do the same maintenance schedule with the Hustler, except oil change every 50 hours. Transmission oil changed during the yearly tune-up. I figure the 2 transmission oil filters and "fresh" transmission oil cheap insurance to help its longevity.
Since mowing with the zero turn, I would never go back to riding tractor. Vey fast turning and less mow time. Now it takes just 60-70 minutes to mow 1.5 acres with 12+ trees to cut around. The Deere took 90 to 135+minutes. Granted the zero turn mower deck is bigger, but others have also told me that their zero deck is the same size as their riding mower deck and it takes less time to mow.