I bought everything for my (2210) 50 hours service last fall. As winter approached, I went ahead and changed the oil at 34 hours. I'll do the hydraulic fluid and filter at 50, and may go ahead and do the oil change again.
I've got 41 hours on it now, 7 hours of snow removal, tilling, spreading, and erosion repair work.
I put 34 hours on the tractor in about the first 3-4 months of ownership so I expect I will probably put between 50 and 100 hours a year on the tractor. Regardless of the maintenance schedule, I would recommend changing the engine oil at least every fall. That way, if the tractor isn't used during the winter it will have clean oil. It has always been my understanding that old "dirty" oil can have potentially harmful effects to engine components if left to sit.