What to look for in a Round Baler

I am interested in buying a new to me round baler. I prefer Deere since I have three dealerships all with 45 miles of me. I have been picture looking at some in my price range. Before I go look at them in person, what are some things to look for when looking at a used round baler? I notice in older posts that some are talking about chains and sprockets and belts, but what else? I have looked at 466, 467, 557, and a 567 online. I prefer net wrap bales. The guy that does my round bales for me now prefers a 4X5 bale and I like the way they fit on our trailer. Dont have much experience with a 5X5 or 5X6 bale...

 

I plan to pull it with a JD 2955. Will it pull these balers on flat land, with grass hay? 

 

There are 3 567s that I have been comparing. The most expensive is 7.5K more than the cheapest, but it says it has the monitor. Can I use the wrap without the monitor or twine only?

 

Any insight would be appreciated.

What to look for in a Round Baler